Thank you! Putting pump in a 350C right now. Finishing it up. Some knucklehead had me driving myself nuts why he said to drill a hole in pump body to prevent front seal from blowing out lol.
@@nickstransmissions that worked great! Customer has several 60's model muscle cars. He said I've got his business, said it's the best shifting 350 he believes he's ever had.
Thanks again, Matt! I believe all GM torque converter bolt patterns up through at least the 6L transmissions are the same...That said, you should also consider engine balance method (internal vs external) whenever swapping flex plates from different years, vintages of engine.
Hi John, thank you for watching. Yes, all those parts will transfer, except any separator plate and/or plate gaskets that may have come with the kit, if it's originally intended for use with the non-lock up variant of TH350. The Transgo springs for the various valve trains will all swap over to the TH350C valve body.
Double-CHECKing here (no pun intended). In regards to a th350c - when eliminating the check balls (except for the one for the modulator valve) - can you remove number 5 (the one for TCC)? I'm NOT converting the th350c...but removing whatever check balls I can. It was unclear to me whether #5 was removed only if converting, or if #5 can be removed altogether when rebuilding a th350c. Thanks!
Ha - like the pun (not intended)...The guidance in that video was specifically for those converting TH350c transmissions to the non-locking variant. For stock TH350c builds using a stock converter, keep all check balls to start then if you want to crispen up the shifts, drill the feed holes in the separator plate, perhaps start with an additional .010 - .013 larger to start then work your way up from there. Keep the #5 TCC check ball regardless. You can obviously do what you would like with the others apart from the modulator check ball (that has to stay) but that's my advice.
@@nickstransmissions I've been watching videos on "dual feed" but not getting responses. Would there be any difference between th350 and th350c for dual feed?
Are you subscribed to the channel? Asking as I have no problem helping folks out (it's why i started the channel) but at the same time subscribers help me also.
Not sure what you mean by "secondary valve thing" but the worm tracks are different between the two cases as pointed out in the video so no, you can't just use the non-lock up VB and plate and forego the other steps... That said, there's an even easier approach if you want to convert a TH350C to a non-locking TH350 without swapping all the hard parts: simply have your converter builder remove the converter clutch from the torque converter and re-weld it back together (if it needs a new stator and other internals, have those replaced at the time), remove the o-ring on the end of the input shaft and plug the feed port to the converter clutch on the aux valve body. Learned this from another trans builder, however I didn't mention in the video as I've never tried it myself.
Essentially I have a fresh non lockup 350 that the case is broke and a lock up core I’m trying to put the fresh parts into, if I’m understanding me putting the fresh internals from the non lock up into the lock case is fine, as in everything pump input shaft drums clutches all of it and the modifications are need in the valve body area? And the non lock valve body won’t work have to use the lock valve body parts and make necessary modifications?
Oh, ok so if you're going to be swapping all the guts from one case to another (non-lock up guts into lock up case and make lock up case, non-locking) then follow the steps in the video. Transfer everything from inside the broken, non-LU case, including the pump and forward drum into the lock up case - inspect all parts before transferring them if you haven't already done so (also look at the direct drum and pump stator - if the pump stator has the steady rest sleeve and three sealing rings for the direct then use a wide bushing on the direct drum and install all sealing rings on the stator for the direct drum...The steady rest is a hardened steel sleeve installed on all 77+ TH350s and is intended to keep the drum from cocking sideways...You can re-use the LU VB and spacer plate since you're using the lock-up case. use a gasket or block off plate for the aux valve body to block the feed hole and block the converter clutch valve in the aux valve body from moving (use a small rod or stiff piece of hose or something similar). Install the wiring harness and solenoid but don't plug anything into the case connector on the side (the solenoid basically functions as a plug in this application). If you don't already have it, id try to find a downloadable version of the ATSG manual for the TH350C as it has those conversion directions for LU to non-LU. ETA: Don't forget to dill the 1/4" hole in the drain back area of the pump body. What year is your non-lock up TH350?
Justin - See my above reply - I made a couple edits to clarify or provide more detail as needed...Post here if you have any additional questions or run into any problems...
@@nickstransmissions the non lock up is out of 78 c10, I’ve been searching for something to help identify more about the lockup trans, it’s one of those unicase or multi bell or whatever that fits Chevy or BOP
Is it possible to "accidently" install a non lockup TC on a th350c? I know it's wrong...but will it "fit"? I want to make sure this guy didn't install the wrong TC. Thanks. Great video by the way!
It will fit and bolt up but the vehicle probably wont go anywhere or if it does, it will last a few miles or so before the input shaft splines get stripped off.
@@nickstransmissions Okay. Thanks for the reply! I just had my th350c rebuilt, and when I put it into drive it slips slightly, then goes. 2nd and 3rd seem fine. What may be bad and what can I replace? I'd like to fix it while it has all new parts. I'm assuming the trans guy messed something up. I only have about 200 miles on it..
You don’t fix anything on it. You take it back to the builder, tell him what’s happening and have him fix it under warranty. More than likely a sealing ring or lip seal is pinched/broken on either the pump or forward apply piston. Check fluid level and look for vaccum leaks . If fluid level is correct and everything is tight with the vacuum thne the builder has to go back into the trans to fix the problem.
@@nickstransmissions I agree. Unfortunately, the guy is having some health issues, and has shut his operation down...and there are no other trans shops near me. I forgot to note that there is a coating of trans fluid on the pan, cross member, and the thin cover that covers the flex plate. Bolts on pan were a bit loose, so I tightened them snug. Fluid level looks fine. I'm going to have to learn how to do this.
Gotcha, that sucks. Drop the pan and check the filter, valve body & aux valve body bolts, make sure none are loose. If no obvious problems with the vbs or anything else under the pan, you will need to pull the trans, remove the pump, intermediate clutch pack to inspect the sealing rings on the pump stator that seal off the forward clutch circuit. If one of those two rings are bad, you simply replace them. If they are ok then the problem is in the forward drum. You will need a clutch spring compressor to compress the return spring assembly and remove the snap ring so you can pull out the piston and inspect/replace the seal. I show all this being done in one of my th350 rebuild series videos. My next video in the th350 rebuild series will cover the reinstallation of the drums, int clutch pack and pump which will help you with reassembly. I should have it on the channel this coming week. If you’re subscribed you will get notified once it has been uploaded.
I have what I think was a th350c. It appears it has been changed. The input shaft is not what a lockup trans one looks like. I bought a shift kit for a non lockup. I know you said parts are same. So that being said. I can use the kit as if it was a non lockup
Yep, shift kits apply to both versions so you can use it with yours. Just double check everything was done to convert the trans to take a non lock up converter. Otherwise, follow the instructions that came w/the kit.
@@nickstransmissions it says on kit not for lockup type. The plate is different and gaskets. Do I just use gaskets and plate included in the kit? I have the trans go 350-1&2. It appears they didn’t have the part blocked off that you said needed blocked unless something fell out before I seen it. It show me using the non lockup brace where I’m assuming the smaller valve body for the lockup goes. They have a gasket for that as well. This is first time sorry wanting to make sure it’s done correct.
Ah, ok - that's right...Transgo provides a separator plate in those kits that (I believe) dual-feeds the direct clutch via the transfer portion of their plate and it would be different for the TH350C (the rest of the parts are common to both). It's been ages since I've installed a shift kit into a TH350/TH350C as you can accomplish what you want in terms of shift feel/firmness, etc without it. Compare their plate to the one that came from your transmission. There shouldn't be any feed ports or other cut outs in the area of the aux valve body and #5 check ball in the case as those are unique to the TH350C. If their plate lacks those then you should be ok to run it provided you swapped in a pump assembly and input shaft (or entire forward drum) from a non-locking TH350. Use the gasket set that came w/the Transgo shift kit (or non-lock up gaskets). Keep the case connecter in to seal off the case. You can use the non-lock up's reverse hold down plate or bolt the Aux VB onto the case but block the feed if its not already blocked.
@@nickstransmissions I wish I could message you another way to show you pictures. The metal plates are different one of bolt holes are in a different spot above the round valve. Is there a way to send you a pic. First time doing this and of course I ran into this lol
Your best bet is to call Transgo. Their tech support is excellent and they will be able to tell you exactly what needs to be done to run their kit in your application. Just give them the details (th350c conversion to non-lock up using the th350c case, etc.) There may be some additional or different things you have to do with their kit to make it work beyond what i've specified in that video.
Unfortunately, no. It may spline on but those input shaft splines will strip off within a couple drive cycles. Overall shaft length and spline engagement lengths are different.
Thank you! Putting pump in a 350C right now. Finishing it up. Some knucklehead had me driving myself nuts why he said to drill a hole in pump body to prevent front seal from blowing out lol.
You're welcome, Jearl!
@@nickstransmissions that worked great! Customer has several 60's model muscle cars. He said I've got his business, said it's the best shifting 350 he believes he's ever had.
Another great video, Nick. Are the flexplates interchangeable between a TH350 and TH350C? Thanks!
Thanks again, Matt!
I believe all GM torque converter bolt patterns up through at least the 6L transmissions are the same...That said, you should also consider engine balance method (internal vs external) whenever swapping flex plates from different years, vintages of engine.
@@nickstransmissions thanks for the clarification, Nick!
You're welcome, Matt!
You mention the valve body valving is the same. Could I use the trans kit from a th350 and put it into a th350-C?
Hi John, thank you for watching.
Yes, all those parts will transfer, except any separator plate and/or plate gaskets that may have come with the kit, if it's originally intended for use with the non-lock up variant of TH350. The Transgo springs for the various valve trains will all swap over to the TH350C valve body.
nice thanks
Double-CHECKing here (no pun intended). In regards to a th350c - when eliminating the check balls (except for the one for the modulator valve) - can you remove number 5 (the one for TCC)? I'm NOT converting the th350c...but removing whatever check balls I can. It was unclear to me whether #5 was removed only if converting, or if #5 can be removed altogether when rebuilding a th350c. Thanks!
Ha - like the pun (not intended)...The guidance in that video was specifically for those converting TH350c transmissions to the non-locking variant.
For stock TH350c builds using a stock converter, keep all check balls to start then if you want to crispen up the shifts, drill the feed holes in the separator plate, perhaps start with an additional .010 - .013 larger to start then work your way up from there. Keep the #5 TCC check ball regardless.
You can obviously do what you would like with the others apart from the modulator check ball (that has to stay) but that's my advice.
@@nickstransmissions I've been watching videos on "dual feed" but not getting responses. Would there be any difference between th350 and th350c for dual feed?
Watch this video - I cover dual feeding the TH350: th-cam.com/video/wEu4ZyU86SM/w-d-xo.html
@@nickstransmissions Same applies to lock up version?
Are you subscribed to the channel?
Asking as I have no problem helping folks out (it's why i started the channel) but at the same time subscribers help me also.
Can you just use the non lockup valve body and plate’s in the lockup case instead of messing with the non lock up secondary valve thing?
Not sure what you mean by "secondary valve thing" but the worm tracks are different between the two cases as pointed out in the video so no, you can't just use the non-lock up VB and plate and forego the other steps...
That said, there's an even easier approach if you want to convert a TH350C to a non-locking TH350 without swapping all the hard parts: simply have your converter builder remove the converter clutch from the torque converter and re-weld it back together (if it needs a new stator and other internals, have those replaced at the time), remove the o-ring on the end of the input shaft and plug the feed port to the converter clutch on the aux valve body. Learned this from another trans builder, however I didn't mention in the video as I've never tried it myself.
Essentially I have a fresh non lockup 350 that the case is broke and a lock up core I’m trying to put the fresh parts into, if I’m understanding me putting the fresh internals from the non lock up into the lock case is fine, as in everything pump input shaft drums clutches all of it and the modifications are need in the valve body area? And the non lock valve body won’t work have to use the lock valve body parts and make necessary modifications?
Oh, ok so if you're going to be swapping all the guts from one case to another (non-lock up guts into lock up case and make lock up case, non-locking) then follow the steps in the video. Transfer everything from inside the broken, non-LU case, including the pump and forward drum into the lock up case - inspect all parts before transferring them if you haven't already done so (also look at the direct drum and pump stator - if the pump stator has the steady rest sleeve and three sealing rings for the direct then use a wide bushing on the direct drum and install all sealing rings on the stator for the direct drum...The steady rest is a hardened steel sleeve installed on all 77+ TH350s and is intended to keep the drum from cocking sideways...You can re-use the LU VB and spacer plate since you're using the lock-up case. use a gasket or block off plate for the aux valve body to block the feed hole and block the converter clutch valve in the aux valve body from moving (use a small rod or stiff piece of hose or something similar). Install the wiring harness and solenoid but don't plug anything into the case connector on the side (the solenoid basically functions as a plug in this application).
If you don't already have it, id try to find a downloadable version of the ATSG manual for the TH350C as it has those conversion directions for LU to non-LU.
ETA: Don't forget to dill the 1/4" hole in the drain back area of the pump body.
What year is your non-lock up TH350?
Justin - See my above reply - I made a couple edits to clarify or provide more detail as needed...Post here if you have any additional questions or run into any problems...
@@nickstransmissions the non lock up is out of 78 c10, I’ve been searching for something to help identify more about the lockup trans, it’s one of those unicase or multi bell or whatever that fits Chevy or BOP
Is it possible to "accidently" install a non lockup TC on a th350c? I know it's wrong...but will it "fit"? I want to make sure this guy didn't install the wrong TC. Thanks. Great video by the way!
It will fit and bolt up but the vehicle probably wont go anywhere or if it does, it will last a few miles or so before the input shaft splines get stripped off.
@@nickstransmissions Okay. Thanks for the reply! I just had my th350c rebuilt, and when I put it into drive it slips slightly, then goes. 2nd and 3rd seem fine. What may be bad and what can I replace? I'd like to fix it while it has all new parts. I'm assuming the trans guy messed something up. I only have about 200 miles on it..
You don’t fix anything on it. You take it back to the builder, tell him what’s happening and have him fix it under warranty. More than likely a sealing ring or lip seal is pinched/broken on either the pump or forward apply piston.
Check fluid level and look for vaccum leaks . If fluid level is correct and everything is tight with the vacuum thne the builder has to go back into the trans to fix the problem.
@@nickstransmissions I agree. Unfortunately, the guy is having some health issues, and has shut his operation down...and there are no other trans shops near me. I forgot to note that there is a coating of trans fluid on the pan, cross member, and the thin cover that covers the flex plate. Bolts on pan were a bit loose, so I tightened them snug. Fluid level looks fine. I'm going to have to learn how to do this.
Gotcha, that sucks.
Drop the pan and check the filter, valve body & aux valve body bolts, make sure none are loose.
If no obvious problems with the vbs or anything else under the pan, you will need to pull the trans, remove the pump, intermediate clutch pack to inspect the sealing rings on the pump stator that seal off the forward clutch circuit. If one of those two rings are bad, you simply replace them. If they are ok then the problem is in the forward drum. You will need a clutch spring compressor to compress the return spring assembly and remove the snap ring so you can pull out the piston and inspect/replace the seal. I show all this being done in one of my th350 rebuild series videos.
My next video in the th350 rebuild series will cover the reinstallation of the drums, int clutch pack and pump which will help you with reassembly. I should have it on the channel this coming week. If you’re subscribed you will get notified once it has been uploaded.
Which valve body gasket should i use on this process
Hi Brady, you can use the lock up versions - the lock up functionality wont be used but otherwise would function the same as the non lock up version.
I have what I think was a th350c. It appears it has been changed. The input shaft is not what a lockup trans one looks like. I bought a shift kit for a non lockup. I know you said parts are same. So that being said. I can use the kit as if it was a non lockup
Yep, shift kits apply to both versions so you can use it with yours. Just double check everything was done to convert the trans to take a non lock up converter. Otherwise, follow the instructions that came w/the kit.
@@nickstransmissions it says on kit not for lockup type. The plate is different and gaskets. Do I just use gaskets and plate included in the kit? I have the trans go 350-1&2. It appears they didn’t have the part blocked off that you said needed blocked unless something fell out before I seen it. It show me using the non lockup brace where I’m assuming the smaller valve body for the lockup goes. They have a gasket for that as well. This is first time sorry wanting to make sure it’s done correct.
Ah, ok - that's right...Transgo provides a separator plate in those kits that (I believe) dual-feeds the direct clutch via the transfer portion of their plate and it would be different for the TH350C (the rest of the parts are common to both). It's been ages since I've installed a shift kit into a TH350/TH350C as you can accomplish what you want in terms of shift feel/firmness, etc without it.
Compare their plate to the one that came from your transmission.
There shouldn't be any feed ports or other cut outs in the area of the aux valve body and #5 check ball in the case as those are unique to the TH350C. If their plate lacks those then you should be ok to run it provided you swapped in a pump assembly and input shaft (or entire forward drum) from a non-locking TH350. Use the gasket set that came w/the Transgo shift kit (or non-lock up gaskets). Keep the case connecter in to seal off the case. You can use the non-lock up's reverse hold down plate or bolt the Aux VB onto the case but block the feed if its not already blocked.
@@nickstransmissions I wish I could message you another way to show you pictures. The metal plates are different one of bolt holes are in a different spot above the round valve. Is there a way to send you a pic. First time doing this and of course I ran into this lol
Your best bet is to call Transgo. Their tech support is excellent and they will be able to tell you exactly what needs to be done to run their kit in your application. Just give them the details (th350c conversion to non-lock up using the th350c case, etc.)
There may be some additional or different things you have to do with their kit to make it work beyond what i've specified in that video.
Is it possible to put a non lockup converter in your th350c and it actually works.
Unfortunately, no. It may spline on but those input shaft splines will strip off within a couple drive cycles. Overall shaft length and spline engagement lengths are different.