4L60E / 700R4 Forward Drum Inspection; 3rd Gear Slipping and Failure
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- เผยแพร่เมื่อ 5 ต.ค. 2024
- This video discusses common problems associated w/the 4L60e and 700R4 forward drum and how to inspect the drum to confirm/deny it's serviceable.
While not mentioned in the video it's also important to carefully look over the drum casting itself for cracks, both inside and outside once it's been emptied of its contents.
You have great informative transmission videos.Thanks for sharing your knowledge.
Glad you like them!
Happy Thanksgiving to you and your family Nick!
Thank you and same for you, Doug.
These are really informative...the only things i keep missing in all these 700R4 tear down and rebuilds....is the lack of consideration of the steel and friction plates....they are not one-for-one stacked....you have a top and bottom plate and sometimes two metal plates are together. I wish there was a sequence on how the plates are re-installed. When i go to do mine...I'm keeping all the original plates in order to re-build the exact same way with the new plates and frictions. I can't believe how every transmission rebuilders just throw around the plates and mix them up...some of those steel plates have different top and bottoms and some are back to back steel together. I'm going to go a lot slower when i do mine....and keep the original stacks in order to learn how it goes back together.
Thanks, man - appreciate the feedback.
The only two plates in the 700R4 3-4 clutch pack that are different are the apply and backing plates...The 700r4 uses a three-element system: The apply plate support, apply plate and backing plate...the steels are all the same, .075" thick and the friction plates are all the same, .080" thick. You can sometimes use 4L60E flat steels if you install a #7 apply ring, and those flat steels are .105" thick.
Some of the other clutch packs use what's called a 'cushion' or 'wavy' plate which is installed to soften engagement into those respective gears...The 700R4 uses a forward wavy plate, a reverse input wavy plate and a low reverse wavy plate in those respective clutch packs...The wavy/cushion plates are always at the bottom of the stack, underneath the bottom-most steel plate. If you haven't done so already, check out my 700R4 rebuild series, I go through the clutch pack installations a little more deliberately so folks can see the order of everything.
The only GM transmission that comes from the factory with two consecutive flat steel plates in any clutch pack is the 200-4R and that uses three flat steels (two back to back), two friction plates and a backing plate.
Also, if you haven't already done so, grab the ATSG manual for the 700R4 (it will be sold as the '4L60' ATSG manual). It's a must have for any builder, especially those rebuilding their first 700R4.
@@nickstransmissions Wow, thank you Nick I will get that ATSG manual. I've rebuilt many things...for myself...I'm going to leave the plate-stacks as-is in order when i removed them. so i can match up all dimensions of the new plate stock going back in (one-by -one) to those original stacks, then check for snap ring clearance and finally end shaft clearance, nothing binding w/ servo outer 2-4 band clearance. I purchased a complete Borg-Warner master kit...might contain 4L60E parts too. I'm not trying to integrated #7 apply ring to use parts from a 4L60E (that's way beyond my knowledge)....i want everything situated as it was. Even the friction plates are different for each section. It'll be fun. I know exactly how to burn up 700R4's (3 differents ways too) so it'll never happen again...now i need to learn how to rebuild them myself. thanks again. When this next 700R4 is installed, it'll never be leaking anywhere (no more silly leaking hot-warped-plastic detent cables, aluminum with o-ring is the best), secondly the TV detent cable will be adjusted perfectly, then a little tighter for good safety measure, and thirdly...only tow in 3rd gear...i forgot just once.
Don't get married to having everything exactly the way it was if your 3-4 clutch clearance is greater than .050...I'd purchase one or two 4L60E 3-4 flat steels which are .105 thick so you can put one or both towards the bottom of the clutch pack to get to between .040-.050 or so clearance in that clutch pack. The steels should be a couple bucks each at a local transmission parts supply house. When installed, the servo assembly should have appx .050-.125 travel before it fully applies the band - install the servo dry with no seals/sealing rings, then install the snap ring...Once done, check travel by mounting a dial indicator somehow so the plunger makes contact with the servo once you have it fully pressed in. Then release it slowly until it makes contact with the cover snap ring and see how much that plunger moved...If you don't have a dial indicator and magnetic base, buy one..Harbor Freight sells a kit relatively inexpensive - you can look into that on their website...Forward clutch should be between .030-.050, Rev input between .040-.070; Low reverse and coast clutch packs are not measured so just use exactly what came out or new equivalents.
Don't forget to pick up a 4L60E rubber/viton seal for the input-output shaft junction location in the forward drum...The plastic seals that are typically provided in the 700R4 kits don't seal very well.
@@nickstransmissions Wow..thank you Nick...those are some great tip on clearances, now i understand the meaning of those thicker plates to achieve the median .45 on the clutch pack. Forward drum seal to be rubber-viton versus plastic...rebuild kit coming in today, i'll check my kit first on that seal.
@@nickstransmissions That is the weakest part of those 700R-4's...losing or slipping in 3rd gear...the 3-4 clutch pack is first to go. I'll make sure that one is .42, tight as i dare to go. Once transmission fluid is on the friction surfaces...doesn't it swell the material tighter? I'm installing my plates dry...i know some rebuilders soak them. Do you soak the larger 2-4 servo controled band?...I'm thinking that's the only one i want to soak overnight.
Thanks for all the info.
You're welcome!
Hi Nick, I found the load spring video you were talking about, and it makes perfect sense what the load springs are for and why you can eliminate them or I guess tune them! all that spinning ATF has to go some where and the compressing the clutch pack is the path of least resistance. I guess just like oil in the crankcase the windage is going to move it somewhere if you don't control it! So in this transmission a larger exhaust is needed in the drum for high performance(high rpm) build? Thanks for your knowledge Nick and your reply!!
Yep...i only install them in 6000+ rpm and/or 500HP type applications when clearance is .030-.040. Otherwise the Transgo high rate return spring kit with bleeder orifice is sufficient to prevent centrifugal apply...
Thanks Nick ,mine failed leak test ,pressed shaft out and had galling at seal area on drum.I was able to polish area out and ready to reassemble shaft.Question is what do I put on shaft splines?I heard loctite.Wanted to know for sure.Thanks man
You're welcome, Joe. I don't try to repair leaking drum-shaft assemblies as i feel the act of pressing the shaft out and back in stresses the drum too much. I just replace leaking drums with ones that dont leak.