For those looking for more detail as to how to do the next step of a full rebuild, there are now a couple of excellent video sets that go into this in detail. The best one I've found so far is by Eric O at South Main Auto, here. th-cam.com/video/ccWhhgLZ20k/w-d-xo.html Also don't miss the video linking to Briansmobile1's video, linked in the comment thread, below. An older set was done by Rickafix, here th-cam.com/video/R-LsFpQkn5M/w-d-xo.html. Also just today I discovered an excellent demonstration of how to press in the seals and bearings, here th-cam.com/video/w4Wv7sw5nLs/w-d-xo.html. Good luck!
I had to drop my NPG 246-NP8 transfer case so I studied your video and found it extremely useful. Now, I have a 2004 GMC Sierra so my transfer case is a little different but it really helped none the less. Thanks for posting a worthwhile video.
Thanks for putting up. After tearing into the the locking hubs and even opening the pumpkin to see if any gears were broken, I'm wishing I would've done this to see if the transfer case was shot first, which it is. New to 4x4's and learning the hard way to get things fixed. 1982 GMC 1/2 ton K1500.
Those are wise remarks. Yes, we repaired the seal leaking at the transfer case side. No more leaking since then, though I didn't do anything to the transmission end. I'll continue to watch that to the future. Thanks for your contribution!
Have a 2001 GMC Yukon 5.3L- been battling the 4WD Service light going on 2 years now. I've tried changing the switch module, TCCM, front diff actuator, oversized fuses and lastly a fluid change out. Will sometimes switch into 4HI, but then the 4WD Service light comes back on and the fuse is popped. I finally got my hands on a used 246 t-case with all the numbers/codes that seem to line up. Great step-by-step procedure- was taking better notes than I ever did in any classroom! Also appreciate the spline count- going to check to make sure they are the same. Before I tear into it tomorrow! Thanks for your assistance
Oh, I'm glad you recorded your experience for the thread here. When I removed the encoder motor (while the case was on the bench) it came off perfectly, and putting it back on was easy too. But maybe in your case it needed more wiggling that wasn't possible in the confines of the vehicle frame. Nothing beats hands-on experience! Thanks again for your contribution.
Thank you for posting this video! I'm in the process of replacing the transfer case on my 2000 Chevy Silverado 1500 z71 and this definitely helped. I'm most likely going to go to a junkyard and pick one up off a wrecked vehicle and use that on my truck to save some cost.
And you were correct to do that. That's what they are called in the actual GM service and parts info. Also, thanks for taking the time to make this video. I usually like to do rebuilds myself but the cost of some of the special tools almost makes it a moot point . On mine the Kent-Moore puller for the rear output bushing is $400 alone. I lucked out and found a used one on ebay for $35 but sometimes it's cheaper to take it to a shop once you get it out.
I am about to replace the NP246 on my 1999 Suburban and decided to get a rebuilt one on eBay for $729 with free shipping and no core charge. It is completely rebuilt: seals, bearings, chain, clutches, steels, pump and etc. As well as an upgraded rear case half. I couldn't justify doing it any other way.. Will be installing it this weekend. :-) Thanx for the good removal tips!
this video is so helpful..i just got my transmission rebuilt...but wen i drove slow in a parking lot with the windows down i heard that noise...same clicking/grinding noise...i thought it was hard to take off and get it fixed....but thanks this vid...i feel more confiedant..and will be even cheaper to take off and put back on my self..save me money on labor...very helpfull..thanks for the video..
Thanks for the video. I got the transfer case out in 1 1/2 hours, went very smooth, now to open it up and see where the problems are at. I was quoted $1000 to trade my core for a rebuilt one which doesn't seem too bad. I don't need my truck for a while so i will mull it over and see what i end up doing. Thanks again.
Great video spelunkerd, you and others here on TH-cam inspired me to not only rebuild my own NP246 TC, but to produce a few videos on the modifications I did as well as the assembly. After getting mine apart it was quite obvious these things were poorly designed and require some modifications to keep them from wearing themselves out prematurely.
Great, I'll have a look. Anybody who cares enough to give back to the TH-cam community by recording experience is OK in my books. Thanks for stopping by to glance at my humble effort, which could easily be eclipsed by somebody who takes the rebuild right through to completion. I drove this car today, it was certainly worth the effort I put in.
Thanks for your input! For others who may be considering doing a case swap, they should know that there is added complexity if the diameter and the number of splines on the input and output shafts differ from the original case. Of course even if there is a problem, it's not insurmountable, just more work.
@JScottRacing I'm glad it helped. Maybe you'll be lucky and it will be a universal joint rather than the case. Helping guys like you is my way of giving back, for all the help I've received from others here on youtube. Thanks for your comment. Dave
I like this video a lot. So many other videos were so full of blabber and fluff. You were straight to the point and hit all the critical points. Thanks again and I thumbs you up.
You are very good communicator as well as technical skill. I learned a lot from you. You are very talented and good on financial justification. Great video.
On mine I could feel the top one but not see it. The side ones were all easily seen. Fortunately they all were on with minimal torque, I was surprised how easily they came off. I used that ratcheting swivel box wrench that I showed in the video. It might help if you clean the area really well -- of course there is a risk to pressure washing but that might make it easier (disconnect battery). It's also a lot more comfortable to work on a clean surface when you lay underneath. Good luck!
That is a very neat video. Your truck is in very nice shape with very little rust to battle. I had front axle issues on my S-10 and I was unable to record it's repair but after watching you, wish I had. The 4x4 system on these trucks (S-10's being similar in design) is quite a beast but there are tricks to figuring out what's going wrong. I ended up setting the whole truck up on jack stands (with the front suspension loaded) to figure out the issues between 2 and 4 wheel drive.
Those are wise words and I agree completely. The rebuild that I had done included replacing the clips that cause erosion through the wall of the casing, though I don't know if the full rebuild form Merchant was done. In any case, it's still working fine today.
Thanks, it does give me hope, I got the the tcase later in the day and once all the prep work was done and getting it under the truck it ate a lot of my time. I'll be giving it another shot in the morning. It just means I need to play with it some more to get it to go into place. Thanks for the advice.
As I recall there was a vent tube that just allows pressure to equalize with atmospheric air, but no vacuum line. The vent tube starts at the case and extends forward, with the forward tip held by a clip above the transmission somewhere.
Rebuilding these yourself is pretty easy. No special tools, really. In addition to bearings and seals, definitely replace tail housing and slip yoke to rear driveline if you've ever run it low on fluid. Likely some wear there that you may or may not see in both slip yoke and tail housing bushing. I found that getting them out is not a challenge but getting them back in is a bit. It's easier if you install the extension housing by itself with one, easy access bolt hand tight to the back of the tranny. You then bring the case in underneath the vehicle 90 degrees rotated then raise it and spin it into position. Get it close to the tranny shaft and take the bolt out of the extension housing. Install the extension housing on the transfer case at this time. You can spin the transfer case to easily gain access to all nuts. Now, slip the whole thing into place and install extension housing bolts. Easy money!
The frustrating thing about doing something like this the first time is not knowing how it goes together. Once I knew what was there, it was much easier. Of course those extra large snap ring pliers helped a lot. Thank you for watching!
Yeah Steve, I was surprised, too. The reason I chose that terminology is that the manual I use (Alldata) uses the same word for that shaft, and I didn't want to confuse anybody by choosing a different word. It wouldn't have been my first choice otherwise (grin).
Yeah, I regret not trying, but that was a time when I couldn't afford to mess it up, and what was available on the net was not complete enough for me to risk it. Hopefully somebody will put together a video of the part I subcontracted, passing a baton for all of us. It's still working fine. Thanks for your comment.
I attach the sliding ears on the trans jack from the bottom so the surface on the pan is smooth and they can be tightened and adjusted while supporting the trans weight. This is the correct way as the bolts are only long enough to remain flush. For the transfer case what is needed is a welded jig that supports it on the jack. It sure is tough getting it back up working alone as brother to the worm!
You want big snap ring pliers, and you want to loosen the bolts that hold the two cases together before trying. Then expand the snap ring and pull the two cases apart. All of a sudden it all falls apart. I think I got lucky since it happened quickly without a lot of fuss, but as you see I had giant pliers. I'm not sure I know of any other tricks. Good luck!
Good video, very informative. One thing worth noting, that I have read about frequently when dealing with this particular transfer case, is that the pump tends to wear a hole in the case due to the thin, sharp edges from the factory. A common pump upgrade kit is available from a company in the US (I think it's Merchant Automotive) which will prevent this.
Yes, you're right, the problem is well described all over the 'net. When mine was rebuilt they installed redesigned clips to prevent that from happening. It's still running strong with no problems.
Good to know. Thanks for the video, I have isolated a drivetrain vibration to the transfer case area and have play in the output shaft along with fluid leaking out so I plan to undergo removing the transfer case soon. I think I will watch this video a few more times before I do..
In response to the remark by faclcom alkhair with the depleted oil -- One of the commonest causes of depleted tranfer case oil with this vintage chev case is a tiny hole eroded in the wall of the case that leaks from there. So, now that oil has been replaced, watch closely for recurrent leaking from the case wall. If the case has formed a hole you need to do an overhaul on it to replace the clips that are designed to protect the inner wall of the case. I've seen people use JB weld for that, but it usually doesn't work until the clips are replaced inside.
thank you for putting this video up.im changing the transfer case myself on my 99 yukon,this video helped me out so much.saved me prob$ 1500 thanks again man.
The outer bearing that supports the output shaft to the rear wheels was badly damaged, and the pitted balls of that bearing were binding as the shaft rotated. I replaced that bearing, the chain and all seals, and I replaced those metal clips that are notorious causes of damage to the case. Thanks for your comment, and good luck!
Oh, how I DON'T want to do this, but I believe I WILL be doing this shortly. I do have a rebuilder I have confidence in that I may ask to do the rebuild, but I need to ask what the price difference is if I do the "remove and replace". Unfortunately, I'll be working in an uneven driveway with cold weather approaching! Sharing this video is invaluable and I appreciate you taking the time. I tried all the lower cost possibilities first (bearings - carrier & wheel, universals (all)). This is it.
I really appreciate your professionalism in editing and eloquent dialog. Your shop also looks very nice and clean. What is that you do professionally if you don't mind my asking?
The encoder motor is fairly easy to remove and it might be safer to remove it before removing the case. I guess the balance is whether you are more likely to damage the encoder by leaving it on and maybe putting strain on the housing when you drop the case, or by removing it. I left it on until the case was out, but if I were to do it again I might remove it first. Duane at realfixesrealfast shows how to remove it while on the vehicle. Regarding your second point, I agree.
great video. I rebuilt numerous GM 246 t-cases, but I am a licensed mechanic. they are not that bad to do, the big thing depends how bad they are on the inside. I have done a few that the chain stretched so bad it was digging into the case. but the biggest thing with these, auto ones being the worst, is a hole wearing through due to the clip on the oil pump. if you catch it in time, just the rear case half and a redesigned clip on the oil pump will work, but if it goes to long, pull the drain plug and nothing comes out except a chunk of metal.
It's great to have a pro stop by, thanks for your comment. You might get a few questions from people about the rebuild part. I believe the guys who rebuilt mine changed to redesigned clips, so the chain wouldn't wear through.
@bigalhurl That little wrench I showed made it easy -- maybe your trans mount is a little different. I couldn't see some of the nuts but I did it easily by feel, and they weren't on very tight at all.
Not sure. I wouldn't count on the assumption they are the same. The ID tag was hard to find on mine, but with a mirror and a light you should be able to find it after you look at where my tag was. The biggest issue is the number of splines on each of the input and output shafts -- even a slight difference could be a big headache when you try to install it. If the tag matches then it's more likely to be worth the risk.
This is where a lift is really handy since the mechanic can stand underneath and pinpoint the problem. Without a lift, you can put the car on jack stands and have a look. Pay close attention to the sway bar bushings and CV axle and all the universal joints. Ericthecarguy did a youtube video of this "how to find a noise" I think was the title. It is VERY RISKY to run the vehicle while on jack stands so I would NOT do that. Move things with your hand and see if you get the noise.
In my case it just slid back into place, though it was helpful to have the transmission jack to hold the weight while I tipped it back and forth. Once I got one bolt lined up I threaded it on a little, and then wiggled to get the others. The splines have to line up, maybe turn the output shaft a little in case the splines are blocking axial motion. Double check to be sure none of the wires are hanging in your way. Sorry I can't offer any more advice.
It may be similar, but it needs to be almost identical. You have to crawl under and identify your transfer case. If you are lucky there will be a metal tag. If not, get a mirror or a small camera and look for a sticker. You can see where mine was, compare. There is no standardized number of input and output splines, which makes it tricky to swap nonidentical cases -- each case is different. If the splines aren't identical you will have problems matching it all up. Good luck!
@MileyCyrus192 That's eventually what I did to get more height. Unfortunately that wasn't my only problem since my little jack stands needed the same treatment, using several partial sheets of plywood. With all wheels on stands, risks are higher. I didn't want to be laying under the vehicle, unless it was broad based and rock solid. Ultimately I got it done, but not without a lot of unnecessary effort, compared to how one with quality tools would have done it. Thanks for you comment!
Dang, since you've enabled contact lock and since a TH-cam glitch won't permit me to reply to your question, I have to put it here and assume you'll stop back. Sure, if the problem is solved by exclusively driving in 2WD, then you know the solution. But, sometimes a problem like this is not so simple. The wheels and axles still need to turn, so if you still get grinding in 2WD with the axles disengaged then there is a problem with that. I suppose if the front axle shifter motor were seized it might be as simple as removing the nut that locks the two axles together, but that would take some examination by a mechanic. Depending on the age and miles (and sentimental value) of the vehicle, it may be time to cut future losses and scrap the truck. These old trucks are really hard on gas, and moving on is sometimes the best option. I'm sorry to hear about your son, Debra.
Wow what an amazing video break down all the information you really know how to make a TH-cam video that's for sure thank you so much for all your help really made it a hell of a lot easier wish you the best hope all is well
Oh, I'm glad it helped. I wish I could have done the full rebuild, but there are other videos out there showing better detail regarding that step. Thanks for watching!
Thanks for the info.. The GM Np246 had some issues.. Electrical issues like the 4x4 switch, encoder motor failure, front actuator motor failure. Test those out first before buying or rebuilding T-case. Other issues Pump rub on the shell and weak clutches.. I would have put the pump rub saver while the T- case was apart and changed the input and output seals.. If you need a stronger T-case go with the NP241 swap..
@MileyCyrus192 You make a good point. I can't imagine losing grip on a heavy object, and dropping it seven feet onto my foot. The reason I don't like my jack is because I couldn't lift the vehicle high enough for the transmission jack (and case) to move freely under the vehicle.
This vehicle was made before all wheel drive became popular. It can be four wheel drive or two wheel drive, depending on where the transfer case shift levers are positioned. Two wheel drive vehicles don't have a transfer case, power just goes from the transmission into the drive shaft and into the rear diff. It's a much simpler system with fewer moving parts. 2WD vehicles are less expensive and also get better gas mileage.
I don't remember for sure, but I think it was about $500. It would have been more for a rebuilt and tested case, less for an unproven junkyard case. Prices here in Canada are higher than in many places in the US. Those cases are so heavy that shipping costs are significant, as well, especially if you have to ship back the core.
Really enjoyed the video! The think the 100 cc's of trans fluid being expelled, as you separated the 246-NP8 (transfer case) from the transmission (4L60E) is a precursor, to the output shaft seal leaking on the transfer case. GM 4WD arrangements are famous for the trans leaking into the TK. With a rebuilt TK the problem is solved! 100cc's is nothing...just the beginning. At 120k I think you should always check the TK for too much fluid, due to this problem, each oil change..
The 246 transfer case is clutch pack operated. Its progressive lock in auto mode and full lock in 4hi and lo. When in 2wd the center axle disconnect disconnects the front axle so the front shaft has no resistance, the friction of the clutch pack being preloaded causes it to spin the front shaft
spelunkerd glad to be of service. yeah i know quite alot about 4WD systems and all wheel drive systems. the best one ive seen thats not on a luxury vehicle and has no electronics is the quadradrive system on the 99-04 Grand cherokee V8. it does the same as GMs autotrac but with a speed sensitive clutch pack thats hydraulically actuated. much like the 246 but no electronics. the T case in question is a NP247
Great content 👌 #I used a regular 🚗 jack no problems sat it on the jack got it high enough work it in place 👍 higherd jack to hold in place tighten nuts up plugged my plugs up then everything worked out great 💪
i suspect the reason why in 2WD mode the front driveshaft spins is because since its a automatic transfer case the clutch pack that is used has very tight tolerances and since theres little to no resistance on the front driveshaft sprocket inside the transfer case it spins along with the rear sprocket. weird isnt it?
Looks like a great video. I'm guessing that my output shaft bearing is bad too as my transfer case sounds like yours. I don't plan on removing the encoder motor as I've been told that it is very very easy to damage the encoder motor and that they are very pricy to replace. I sure wish that there was a video on a complete disambly and reasembly of this model transfer case somewhere. I've searched all over for manuals on this model transfer case and can't find any.
Ill have to agree... I'm currently removing my Transfer case... RIGHT NOW. I am having problem with the bolts especially the lowest one. the transmission mount seems to completely block this one off. Did you experience this problem?
If the repair was done recently and if the problem is there since the clutch was replaced then I would take it back to the shop that did it. Most mechanics appreciate the opportunity to make things right if the repair didn't work properly. They will usually get the vehicle on a lift for a free proper diagnostic that can't be done on the ground. I would not discount the chance that fixing the clutch made other problems more obvious, but common sense would say to look for other things.
I know this is old but you are correct, my 1999 silverado has the same transfer case and the front driveshaft always turns on it as well (but leaks around the pinion seal too unfortunately lol)
Well I just bought a cam and i will do a thorough rebuild walk through of my rebuilding of a NP246. What recording software do you use to capture and edit? thanks
That could be simple or complex. When my vehicle was on warranty that happened to mine, so I took it to the dealer and they fixed it in a few minutes. It was no big deal, I think it was a wire. If you want to try and fix it yourself, you will want to have a high quality code scanner that can read dealer-specific codes -- most generic scanners can't. Without a scanner to help, you are faced with getting underneath and checking out the encoder motor. Realfixesreal fast did a video of that.
Nice video on the transfer case. I just dropped my np246 and looking for a good snap ring pliers to get the first snap ring off so I can take the cover off. I guess the $20 ones at Pepboys is not going to cut it. What was the span on the snap ring pliers you used to get the first ring off??? Thanks
@doug5790 I hope it works for you. The common leak that I know about is caused by a metal brace for the pump, rubbing on the inner aspect of the magnesium alloy case. Any permanent solution needs to stop that internal rubbing action, or the problem is going to recur. Down lower in this thread there is reference to a Merchant automotive kit. I've never put one of those in, but it might be worth a look....
Its easy you have to pull all the seals to uncover hidden snap rings and the shafts pull out to replace bearings..these bearings are not pressed and held in by more snap rings..you will have to tap a few into place installing but be gentle and use freezer to shrink bearing for inner placements and heat to expand for outer placements.
Has the sun shell failed in your transmission yet? Just about every 4L60E transmission produced has had it happen. It happened to my 2001 Tahoe 2wd at 42,000 miles. Luckily, It was fixed under warranty.
so what specific part do you believe was causing the noise. you said the main rear output bearing was badly damaged. do you think if just that bearing was changed the problem would have been solved. thanks
@iamchevyman5 It was about $800 Canadian, including tax and labour to do the work. They would sell me a rebuild kit (including chain, bearings and seals) for about $375 if I did it myself, but I didn't have the confidence to do that part, and I could not afford to mess that up. Local auto wreckers were selling untested transfer cases for $800, and rebuilt/tested cases were about $1500. I believe it may be cheaper in the more competitive US market.
@spelunkerd Mine is in the shop waitin for a used t-case to be installed now (3,000 dollars!!) My mechanic will not open my unit up so after i get the truck back i'm gonna dive in and install the MA kit into my truck myself, 2002 gmc sierra 2500 Diesel 317,000 km! Thx for the informative video
Thanks for the reply, I was mostly referring to if the method would be identical. Was just wondering because I had a bigger TC. So, I'm guessing it would just be heavier, now other surprises? I haven't checked what one I have yet, but its either the 261HD or 263HD. Them buggers are expensive, so I might look for someone to rebuild it for me. Thanks!
HI, I'm in the middle of the removal. the shafts are gone, and I owuld be removing all the connectors if my worklamp wouldn't have run out of juice. lol I've removed one ocnnector. It's a real PITA. there is a plastic piece that is to be removed so you can press the tab and release the plugs.
Great video. Did you conclude that there was a problem with the transfer case that caused the front axle to turn constantly or is it designed to do that? I noticed that you have 300,000 km on the odometer, any thoughts about how much more life it has in it?
I saw a comment saying " why did you post the video" People shouldn't complain about little things, for me it's enough to try and know when to stop most of your videos have a professional end result and not all about automotive ... How many things can he do with excellent results? ...
That would be a huge addition, please send me a note when you have it posted. I use Premier Pro CS4, which I bought as a master suite when my son was in university. University students get Adobe products at 80% discount and you can get photoshop, premier pro, and a whole lot more for about $600. Note however that it takes a few hundred hours to become proficient. Apple make competitive and much cheaper software, though top line software will be expensive no matter what.
Had that same noise from my 2000 BLAZER , Found that Rear Dif. was full of Gear teeth and was running on Driver wheel only till it Locked up ! Never ran it low on gear oil ,.
The fluid draining out of that case looks awfully dark. What fluid does it use. My Ford and Dodge both use ATF, so I was expecting to see red or something akin to it. Just curious...
@fomoco300k Coolest fluid I've ever seen, it's BLUE in color, unlike any oil I've used! It's AC Delco Autotrak II fluid, OEM part # 10953626, shown at 15:21 of the video. You need 2 1/2 litres, only available from the dealer. Each transfer case is different, so check Alldata or the service manual for your case. Thanks for your comment.
I just had my transfer case replaced in my 2002 suburban for 2100.00. When I picked it up, I drove about 6 miles and started to hear a knocking in engine area and my check engine oil pressure light came on. My oil gauge showed 0. My oil still had 1000 miles to go before changing. Do you think something happened when they were replacing my transfer case or unfortunate coincidence?
Your the first person I've found that truck is doing the same exact thing... I have a 2000 model Chevrolet Silverado Z71 & it started making this clicking noise about 8months ago & it got loud like yours about 3months ago, Unfortunately I drove it to long like that & last week it locked up & through my rear drive shaft off out of my truck & ripped itself off my tranny & it literally shredded the adapter plate from the transfer case to the tranny like it was a piece of paper y I was doin 80mph.
For those looking for more detail as to how to do the next step of a full rebuild, there are now a couple of excellent video sets that go into this in detail. The best one I've found so far is by Eric O at South Main Auto, here. th-cam.com/video/ccWhhgLZ20k/w-d-xo.html
Also don't miss the video linking to Briansmobile1's video, linked in the comment thread, below.
An older set was done by Rickafix, here th-cam.com/video/R-LsFpQkn5M/w-d-xo.html. Also just today I discovered an excellent demonstration of how to press in the seals and bearings, here th-cam.com/video/w4Wv7sw5nLs/w-d-xo.html. Good luck!
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I had to drop my NPG 246-NP8 transfer case so I studied your video and found it extremely useful. Now, I have a 2004 GMC Sierra so my transfer case is a little different but it really helped none the less. Thanks for posting a worthwhile video.
Thanks for putting up. After tearing into the the locking hubs and even opening the pumpkin to see if any gears were broken, I'm wishing I would've done this to see if the transfer case was shot first, which it is. New to 4x4's and learning the hard way to get things fixed. 1982 GMC 1/2 ton K1500.
Those are wise remarks. Yes, we repaired the seal leaking at the transfer case side. No more leaking since then, though I didn't do anything to the transmission end. I'll continue to watch that to the future. Thanks for your contribution!
Have a 2001 GMC Yukon 5.3L- been battling the 4WD Service light going on 2 years now. I've tried changing the switch module, TCCM, front diff actuator, oversized fuses and lastly a fluid change out. Will sometimes switch into 4HI, but then the 4WD Service light comes back on and the fuse is popped.
I finally got my hands on a used 246 t-case with all the numbers/codes that seem to line up. Great step-by-step procedure- was taking better notes than I ever did in any classroom! Also appreciate the spline count- going to check to make sure they are the same. Before I tear into it tomorrow! Thanks for your assistance
I'm sure that many of those who read the comments will find your remarks helpful. Thanks again for your insightful contributions.
For anybody reading this and considering a DIY rebuild, you will want to watch Rickafix1 do it without a lot of fancy tools. Great series!
Oh, I'm glad you recorded your experience for the thread here. When I removed the encoder motor (while the case was on the bench) it came off perfectly, and putting it back on was easy too. But maybe in your case it needed more wiggling that wasn't possible in the confines of the vehicle frame. Nothing beats hands-on experience! Thanks again for your contribution.
Thank you for posting this video! I'm in the process of replacing the transfer case on my 2000 Chevy Silverado 1500 z71 and this definitely helped. I'm most likely going to go to a junkyard and pick one up off a wrecked vehicle and use that on my truck to save some cost.
Good luck!
And you were correct to do that. That's what they are called in the actual GM service and parts info. Also, thanks for taking the time to make this video. I usually like to do rebuilds myself but the cost of some of the special tools almost makes it a moot point . On mine the Kent-Moore puller for the rear output bushing is $400 alone. I lucked out and found a used one on ebay for $35 but sometimes it's cheaper to take it to a shop once you get it out.
I am about to replace the NP246 on my 1999 Suburban and decided to get a rebuilt one on eBay for $729 with free shipping and no core charge. It is completely rebuilt: seals, bearings, chain, clutches, steels, pump and etc. As well as an upgraded rear case half. I couldn't justify doing it any other way.. Will be installing it this weekend. :-) Thanx for the good removal tips!
this video is so helpful..i just got my transmission rebuilt...but wen i drove slow in a parking lot with the windows down i heard that noise...same clicking/grinding noise...i thought it was hard to take off and get it fixed....but thanks this vid...i feel more confiedant..and will be even cheaper to take off and put back on my self..save me money on labor...very helpfull..thanks for the video..
Thanks for the video. I got the transfer case out in 1 1/2 hours, went very smooth, now to open it up and see where the problems are at. I was quoted $1000 to trade my core for a rebuilt one which doesn't seem too bad. I don't need my truck for a while so i will mull it over and see what i end up doing. Thanks again.
Great video spelunkerd, you and others here on TH-cam inspired me to not only rebuild my own NP246 TC, but to produce a few videos on the modifications I did as well as the assembly. After getting mine apart it was quite obvious these things were poorly designed and require some modifications to keep them from wearing themselves out prematurely.
Great, I'll have a look. Anybody who cares enough to give back to the TH-cam community by recording experience is OK in my books. Thanks for stopping by to glance at my humble effort, which could easily be eclipsed by somebody who takes the rebuild right through to completion. I drove this car today, it was certainly worth the effort I put in.
Great video, very informative, great camera clarity and placement. First automotive video I have no complaints about.
+Noah Arca Thank you.
Thanks for your input! For others who may be considering doing a case swap, they should know that there is added complexity if the diameter and the number of splines on the input and output shafts differ from the original case. Of course even if there is a problem, it's not insurmountable, just more work.
@JScottRacing I'm glad it helped. Maybe you'll be lucky and it will be a universal joint rather than the case. Helping guys like you is my way of giving back, for all the help I've received from others here on youtube. Thanks for your comment.
Dave
I like this video a lot. So many other videos were so full of blabber and fluff. You were straight to the point and hit all the critical points. Thanks again and I thumbs you up.
+Jason Jones Thanks!
You are very good communicator as well as technical skill. I learned a lot from you. You are very talented and good on financial justification. Great video.
On mine I could feel the top one but not see it. The side ones were all easily seen. Fortunately they all were on with minimal torque, I was surprised how easily they came off. I used that ratcheting swivel box wrench that I showed in the video. It might help if you clean the area really well -- of course there is a risk to pressure washing but that might make it easier (disconnect battery). It's also a lot more comfortable to work on a clean surface when you lay underneath. Good luck!
Yes, that's the video I was referring to. It's not necessarily his problem, but it gives a good view of how to install and remove the encoder motor.
That is a very neat video. Your truck is in very nice shape with very little rust to battle. I had front axle issues on my S-10 and I was unable to record it's repair but after watching you, wish I had. The 4x4 system on these trucks (S-10's being similar in design) is quite a beast but there are tricks to figuring out what's going wrong. I ended up setting the whole truck up on jack stands (with the front suspension loaded) to figure out the issues between 2 and 4 wheel drive.
Those are wise words and I agree completely. The rebuild that I had done included replacing the clips that cause erosion through the wall of the casing, though I don't know if the full rebuild form Merchant was done. In any case, it's still working fine today.
Thanks, it does give me hope, I got the the tcase later in the day and once all the prep work was done and getting it under the truck it ate a lot of my time. I'll be giving it another shot in the morning. It just means I need to play with it some more to get it to go into place. Thanks for the advice.
Knowing how much work this is, I am not at all surprised at your bill -- it sounds very reasonable to me.
As I recall there was a vent tube that just allows pressure to equalize with atmospheric air, but no vacuum line. The vent tube starts at the case and extends forward, with the forward tip held by a clip above the transmission somewhere.
Rebuilding these yourself is pretty easy. No special tools, really. In addition to bearings and seals, definitely replace tail housing and slip yoke to rear driveline if you've ever run it low on fluid. Likely some wear there that you may or may not see in both slip yoke and tail housing bushing. I found that getting them out is not a challenge but getting them back in is a bit. It's easier if you install the extension housing by itself with one, easy access bolt hand tight to the back of the tranny. You then bring the case in underneath the vehicle 90 degrees rotated then raise it and spin it into position. Get it close to the tranny shaft and take the bolt out of the extension housing. Install the extension housing on the transfer case at this time. You can spin the transfer case to easily gain access to all nuts. Now, slip the whole thing into place and install extension housing bolts. Easy money!
Thanks for an insightful note that will help many others who stop by.
Great video --I am right in the middle of removal / replacing my GM 246 transfer case ---wish I had seen your video before I started!
The frustrating thing about doing something like this the first time is not knowing how it goes together. Once I knew what was there, it was much easier. Of course those extra large snap ring pliers helped a lot. Thank you for watching!
Yeah Steve, I was surprised, too. The reason I chose that terminology is that the manual I use (Alldata) uses the same word for that shaft, and I didn't want to confuse anybody by choosing a different word. It wouldn't have been my first choice otherwise (grin).
Yeah, I regret not trying, but that was a time when I couldn't afford to mess it up, and what was available on the net was not complete enough for me to risk it. Hopefully somebody will put together a video of the part I subcontracted, passing a baton for all of us. It's still working fine. Thanks for your comment.
Thank you for the informative video. Still very useful in 2022. I'm driving a 2001 Yukon XL. No issues yet, but this is good info.
I attach the sliding ears on the trans jack from the bottom so the surface on the pan is smooth and they can be tightened and adjusted while supporting the trans weight. This is the correct way as the bolts are only long enough to remain flush. For the transfer case what is needed is a welded jig that supports it on the jack. It sure is tough getting it back up working alone as brother to the worm!
this is definitely me right now. excellent video. thanks for diagnosing my sounds...
Hey, thanks for your comment. Remarks from guys like yourself, with experience, make this thread more helpful for everybody.
You want big snap ring pliers, and you want to loosen the bolts that hold the two cases together before trying. Then expand the snap ring and pull the two cases apart. All of a sudden it all falls apart. I think I got lucky since it happened quickly without a lot of fuss, but as you see I had giant pliers. I'm not sure I know of any other tricks. Good luck!
Good video, very informative. One thing worth noting, that I have read about frequently when dealing with this particular transfer case, is that the pump tends to wear a hole in the case due to the thin, sharp edges from the factory. A common pump upgrade kit is available from a company in the US (I think it's Merchant Automotive) which will prevent this.
Yes, you're right, the problem is well described all over the 'net. When mine was rebuilt they installed redesigned clips to prevent that from happening. It's still running strong with no problems.
Good to know. Thanks for the video, I have isolated a drivetrain vibration to the transfer case area and have play in the output shaft along with fluid leaking out so I plan to undergo removing the transfer case soon. I think I will watch this video a few more times before I do..
In response to the remark by faclcom alkhair with the depleted oil -- One of the commonest causes of depleted tranfer case oil with this vintage chev case is a tiny hole eroded in the wall of the case that leaks from there. So, now that oil has been replaced, watch closely for recurrent leaking from the case wall. If the case has formed a hole you need to do an overhaul on it to replace the clips that are designed to protect the inner wall of the case. I've seen people use JB weld for that, but it usually doesn't work until the clips are replaced inside.
Who were the idiots that downvoted this?! Thanks for a great no-nonsense video.
thank you for putting this video up.im changing the transfer case myself on my 99 yukon,this video helped me out so much.saved me prob$ 1500 thanks again man.
The outer bearing that supports the output shaft to the rear wheels was badly damaged, and the pitted balls of that bearing were binding as the shaft rotated. I replaced that bearing, the chain and all seals, and I replaced those metal clips that are notorious causes of damage to the case. Thanks for your comment, and good luck!
Oh, how I DON'T want to do this, but I believe I WILL be doing this shortly. I do have a rebuilder I have confidence in that I may ask to do the rebuild, but I need to ask what the price difference is if I do the "remove and replace". Unfortunately, I'll be working in an uneven driveway with cold weather approaching!
Sharing this video is invaluable and I appreciate you taking the time. I tried all the lower cost possibilities first (bearings - carrier & wheel, universals (all)). This is it.
I really appreciate your professionalism in editing and eloquent dialog. Your shop also looks very nice and clean. What is that you do professionally if you don't mind my asking?
The encoder motor is fairly easy to remove and it might be safer to remove it before removing the case. I guess the balance is whether you are more likely to damage the encoder by leaving it on and maybe putting strain on the housing when you drop the case, or by removing it. I left it on until the case was out, but if I were to do it again I might remove it first. Duane at realfixesrealfast shows how to remove it while on the vehicle.
Regarding your second point, I agree.
great video. I rebuilt numerous GM 246 t-cases, but I am a licensed mechanic. they are not that bad to do, the big thing depends how bad they are on the inside. I have done a few that the chain stretched so bad it was digging into the case. but the biggest thing with these, auto ones being the worst, is a hole wearing through due to the clip on the oil pump. if you catch it in time, just the rear case half and a redesigned clip on the oil pump will work, but if it goes to long, pull the drain plug and nothing comes out except a chunk of metal.
It's great to have a pro stop by, thanks for your comment. You might get a few questions from people about the rebuild part. I believe the guys who rebuilt mine changed to redesigned clips, so the chain wouldn't wear through.
@bigalhurl That little wrench I showed made it easy -- maybe your trans mount is a little different. I couldn't see some of the nuts but I did it easily by feel, and they weren't on very tight at all.
Thank you very much for taking the time and effort to put this video together and share your experience/expertise. I found it very helpful, Ciao, L
Thanks!
Not sure. I wouldn't count on the assumption they are the same. The ID tag was hard to find on mine, but with a mirror and a light you should be able to find it after you look at where my tag was. The biggest issue is the number of splines on each of the input and output shafts -- even a slight difference could be a big headache when you try to install it. If the tag matches then it's more likely to be worth the risk.
This is where a lift is really handy since the mechanic can stand underneath and pinpoint the problem. Without a lift, you can put the car on jack stands and have a look. Pay close attention to the sway bar bushings and CV axle and all the universal joints. Ericthecarguy did a youtube video of this "how to find a noise" I think was the title. It is VERY RISKY to run the vehicle while on jack stands so I would NOT do that. Move things with your hand and see if you get the noise.
In my case it just slid back into place, though it was helpful to have the transmission jack to hold the weight while I tipped it back and forth. Once I got one bolt lined up I threaded it on a little, and then wiggled to get the others. The splines have to line up, maybe turn the output shaft a little in case the splines are blocking axial motion. Double check to be sure none of the wires are hanging in your way. Sorry I can't offer any more advice.
@Oldsmob455 Yeah, when the load is off center it's awkward, and lining up the bolts was time consuming. Thanks for your comment.
It may be similar, but it needs to be almost identical. You have to crawl under and identify your transfer case. If you are lucky there will be a metal tag. If not, get a mirror or a small camera and look for a sticker. You can see where mine was, compare. There is no standardized number of input and output splines, which makes it tricky to swap nonidentical cases -- each case is different. If the splines aren't identical you will have problems matching it all up. Good luck!
@MileyCyrus192 That's eventually what I did to get more height. Unfortunately that wasn't my only problem since my little jack stands needed the same treatment, using several partial sheets of plywood. With all wheels on stands, risks are higher. I didn't want to be laying under the vehicle, unless it was broad based and rock solid. Ultimately I got it done, but not without a lot of unnecessary effort, compared to how one with quality tools would have done it.
Thanks for you comment!
Dang, since you've enabled contact lock and since a TH-cam glitch won't permit me to reply to your question, I have to put it here and assume you'll stop back.
Sure, if the problem is solved by exclusively driving in 2WD, then you know the solution. But, sometimes a problem like this is not so simple. The wheels and axles still need to turn, so if you still get grinding in 2WD with the axles disengaged then there is a problem with that. I suppose if the front axle shifter motor were seized it might be as simple as removing the nut that locks the two axles together, but that would take some examination by a mechanic. Depending on the age and miles (and sentimental value) of the vehicle, it may be time to cut future losses and scrap the truck. These old trucks are really hard on gas, and moving on is sometimes the best option. I'm sorry to hear about your son, Debra.
You're welcome, thanks for responding back.
Wow what an amazing video break down all the information you really know how to make a TH-cam video that's for sure thank you so much for all your help really made it a hell of a lot easier wish you the best hope all is well
Oh, I'm glad it helped. I wish I could have done the full rebuild, but there are other videos out there showing better detail regarding that step. Thanks for watching!
You're welcome. Up here in Canada, things cost a lot more, and so I expect you should be able to do better.
Thanks for the info.. The GM Np246 had some issues.. Electrical issues like the 4x4 switch, encoder motor failure, front actuator motor failure. Test those out first before buying or rebuilding T-case. Other issues Pump rub on the shell and weak clutches.. I would have put the pump rub saver while the T- case was apart and changed the input and output seals.. If you need a stronger T-case go with the NP241 swap..
Excellent points, thanks for stopping by. Yes, all three seals were swapped and new clips were installed to prevent pump rub.
@MileyCyrus192 You make a good point. I can't imagine losing grip on a heavy object, and dropping it seven feet onto my foot. The reason I don't like my jack is because I couldn't lift the vehicle high enough for the transmission jack (and case) to move freely under the vehicle.
This vehicle was made before all wheel drive became popular. It can be four wheel drive or two wheel drive, depending on where the transfer case shift levers are positioned. Two wheel drive vehicles don't have a transfer case, power just goes from the transmission into the drive shaft and into the rear diff. It's a much simpler system with fewer moving parts. 2WD vehicles are less expensive and also get better gas mileage.
Yes, I'm told that is normal and your explanation is what I was thinking.
I don't remember for sure, but I think it was about $500. It would have been more for a rebuilt and tested case, less for an unproven junkyard case. Prices here in Canada are higher than in many places in the US. Those cases are so heavy that shipping costs are significant, as well, especially if you have to ship back the core.
Really enjoyed the video! The think the 100 cc's of trans fluid being expelled, as you separated the 246-NP8 (transfer case) from the transmission (4L60E) is a precursor, to the output shaft seal leaking on the transfer case. GM 4WD arrangements are famous for the trans leaking into the TK. With a rebuilt TK the problem is solved! 100cc's is nothing...just the beginning. At 120k I think you should always check the TK for too much fluid, due to this problem, each oil change..
The 246 transfer case is clutch pack operated. Its progressive lock in auto mode and full lock in 4hi and lo. When in 2wd the center axle disconnect disconnects the front axle so the front shaft has no resistance, the friction of the clutch pack being preloaded causes it to spin the front shaft
That certainly is consistent with what I saw. Thanks for stopping by with an explanation.
spelunkerd
glad to be of service. yeah i know quite alot about 4WD systems and all wheel drive systems.
the best one ive seen thats not on a luxury vehicle and has no electronics is the quadradrive system on the 99-04 Grand cherokee V8. it does the same as GMs autotrac but with a speed sensitive clutch pack thats hydraulically actuated. much like the 246 but no electronics. the T case in question is a NP247
Yes, and after the fix that rotation continued, as you say.
Great content 👌 #I used a regular 🚗 jack no problems sat it on the jack got it high enough work it in place 👍 higherd jack to hold in place tighten nuts up plugged my plugs up then everything worked out great 💪
Very good and informative video. Thank you for taking the time to walk a guy (or girl. lol) through a transfer case job!
i suspect the reason why in 2WD mode the front driveshaft spins is because since its a automatic transfer case the clutch pack that is used has very tight tolerances and since theres little to no resistance on the front driveshaft sprocket inside the transfer case it spins along with the rear sprocket. weird isnt it?
Looks like a great video. I'm guessing that my output shaft bearing is bad too as my transfer case sounds like yours.
I don't plan on removing the encoder motor as I've been told that it is very very easy to damage the encoder motor and that they are very pricy to replace.
I sure wish that there was a video on a complete disambly and reasembly of this model transfer case somewhere. I've searched all over for manuals on this model transfer case and can't find any.
Ill have to agree... I'm currently removing my Transfer case... RIGHT NOW. I am having problem with the bolts especially the lowest one. the transmission mount seems to completely block this one off. Did you experience this problem?
If the repair was done recently and if the problem is there since the clutch was replaced then I would take it back to the shop that did it. Most mechanics appreciate the opportunity to make things right if the repair didn't work properly. They will usually get the vehicle on a lift for a free proper diagnostic that can't be done on the ground. I would not discount the chance that fixing the clutch made other problems more obvious, but common sense would say to look for other things.
I know this is old but you are correct, my 1999 silverado has the same transfer case and the front driveshaft always turns on it as well (but leaks around the pinion seal too unfortunately lol)
Well I just bought a cam and i will do a thorough rebuild walk through of my rebuilding of a NP246. What recording software do you use to capture and edit? thanks
That could be simple or complex. When my vehicle was on warranty that happened to mine, so I took it to the dealer and they fixed it in a few minutes. It was no big deal, I think it was a wire. If you want to try and fix it yourself, you will want to have a high quality code scanner that can read dealer-specific codes -- most generic scanners can't. Without a scanner to help, you are faced with getting underneath and checking out the encoder motor. Realfixesreal fast did a video of that.
I'm glad it helped, thanks for the feedback.
Thank you so much. This has been a very helpful & instructional video. Thanks again
You're welcome, I'm glad it helped.
Nice video on the transfer case. I just dropped my np246 and looking for a good snap ring pliers to get the first snap ring off so I can take the cover off. I guess the $20 ones at Pepboys is not going to cut it. What was the span on the snap ring pliers you used to get the first ring off??? Thanks
@doug5790 I hope it works for you. The common leak that I know about is caused by a metal brace for the pump, rubbing on the inner aspect of the magnesium alloy case. Any permanent solution needs to stop that internal rubbing action, or the problem is going to recur. Down lower in this thread there is reference to a Merchant automotive kit. I've never put one of those in, but it might be worth a look....
My yukon needs to be replaced , I'm going to try and Handel this alone. Ugh wish me luck, thanks for the video
It's not too hard, and the reward can stay with you forever if you are successful. Good luck!
spelunkerd i guess I'll have to have it rebuild and I'm feeling overwhelmed. Do you have another video showing the rebuilding?
There are a few out there, search TH-cam.
Its easy you have to pull all the seals to uncover hidden snap rings and the shafts pull out to replace bearings..these bearings are not pressed and held in by more snap rings..you will have to tap a few into place installing but be gentle and use freezer to shrink bearing for inner placements and heat to expand for outer placements.
Joshua Webber I replaced the transfer case it while ago, took me two days but it's done
I will be using your video as a guide. Very thorough. Thanks for posting it.
Has the sun shell failed in your transmission yet? Just about every 4L60E transmission produced has had it happen. It happened to my 2001 Tahoe 2wd at 42,000 miles. Luckily, It was fixed under warranty.
Great and thorough video, thank you for posting.
so what specific part do you believe was causing the noise. you said the main rear output bearing was badly damaged. do you think if just that bearing was changed the problem would have been solved. thanks
@iamchevyman5 It was about $800 Canadian, including tax and labour to do the work. They would sell me a rebuild kit (including chain, bearings and seals) for about $375 if I did it myself, but I didn't have the confidence to do that part, and I could not afford to mess that up. Local auto wreckers were selling untested transfer cases for $800, and rebuilt/tested cases were about $1500. I believe it may be cheaper in the more competitive US market.
@spelunkerd Mine is in the shop waitin for a used t-case to be installed now (3,000 dollars!!) My mechanic will not open my unit up so after i get the truck back i'm gonna dive in and install the MA kit into my truck myself, 2002 gmc sierra 2500 Diesel 317,000 km! Thx for the informative video
Great job man I hope its still workig right . Its always a hard job to pull a trans and diferetal
good video and if your not fully comfortable in doing a job there is no shame in letting someone with more knowledge handle it.
Thanks for the reply, I was mostly referring to if the method would be identical. Was just wondering because I had a bigger TC. So, I'm guessing it would just be heavier, now other surprises? I haven't checked what one I have yet, but its either the 261HD or 263HD. Them buggers are expensive, so I might look for someone to rebuild it for me. Thanks!
16:00 I use 2x12 flat blocks stacked, glued, n screwed for extra height. Even add sheet metal on top if concerned.
Fur the jack stands
HI, I'm in the middle of the removal. the shafts are gone, and I owuld be removing all the connectors if my worklamp wouldn't have run out of juice. lol
I've removed one ocnnector. It's a real PITA. there is a plastic piece that is to be removed so you can press the tab and release the plugs.
Great video. Did you conclude that there was a problem with the transfer case that caused the front axle to turn constantly or is it designed to do that? I noticed that you have 300,000 km on the odometer, any thoughts about how much more life it has in it?
I saw a comment saying " why did you post the video"
People shouldn't complain about little things, for me it's enough to try and know when to stop most of your videos have a professional end result and not all about automotive ... How many things can he do with excellent results? ...
Thanks. My 98 Tahoe makes the exact same clicking noise. Time to get to work.
That would be a huge addition, please send me a note when you have it posted. I use Premier Pro CS4, which I bought as a master suite when my son was in university. University students get Adobe products at 80% discount and you can get photoshop, premier pro, and a whole lot more for about $600. Note however that it takes a few hundred hours to become proficient. Apple make competitive and much cheaper software, though top line software will be expensive no matter what.
Had that same noise from my 2000 BLAZER , Found that Rear Dif. was full of Gear teeth and was running on Driver wheel only till it Locked up ! Never ran it low on gear oil ,.
The fluid draining out of that case looks awfully dark. What fluid does it use. My Ford and Dodge both use ATF, so I was expecting to see red or something akin to it. Just curious...
@fomoco300k Coolest fluid I've ever seen, it's BLUE in color, unlike any oil I've used! It's AC Delco Autotrak II fluid, OEM part # 10953626, shown at 15:21 of the video.
You need 2 1/2 litres, only available from the dealer. Each transfer case is different, so check Alldata or the service manual for your case. Thanks for your comment.
Would a transfer case from a 4L80 transmission(floor shift 4x4) in a 2500HD be pretty close to the same thing? I believe its a 261, but not positive.
I just had my transfer case replaced in my 2002 suburban for 2100.00. When I picked it up, I drove about 6 miles and started to hear a knocking in engine area and my check engine oil pressure light came on. My oil gauge showed 0. My oil still had 1000 miles to go before changing. Do you think something happened when they were replacing my transfer case or unfortunate coincidence?
@techgood Your welcome, thank you back.
Your the first person I've found that truck is doing the same exact thing... I have a 2000 model Chevrolet Silverado Z71 & it started making this clicking noise about 8months ago & it got loud like yours about 3months ago, Unfortunately I drove it to long like that & last week it locked up & through my rear drive shaft off out of my truck & ripped itself off my tranny & it literally shredded the adapter plate from the transfer case to the tranny like it was a piece of paper y I was doin 80mph.