Rebuilding my TH400

Fretting ring number 59, retaining ring 47. Its easy to get these confused.

42 is the thicker beveled snap ring that goes to the top. But if these 3 rings get out of order, the center support would not go all the way down

 

Vertical install helps slide everything in, if you cant get it, try pulling g it all out and see if just the center support slide in as it should without getting snagged on the case lugs, if it does and goes all the way down it just means either the parts below are not fully together, or a washer or something slid keeping g parts apart

 

Thank you for that pic. I definitely don't have the fretting ring for my case just the retaining ring and beveled snap ring. I haven't tried it yet but I will definitely pull it apart and try just installing the center support like you suggested.

 

On models with out the ring, sometime the center support eats into the case a little as the support works against the case.

One thing on 400s given the age, never assume all the parts that are in there orginal. Your dealing with a 51 year old parts, there is no way to know if it's ever been into or had parts replaced. Seen many mismatched components b4

 

That's very true who knows who's done what in there! From what I've seen in this trans though it looks to be all original everything has GM on it somewhere and 68 date codes. The only thing that looks to be tampered with is somebody put a b&m shift kit in it. Atleast I know I've changed everything and upgraded it to be stronger and more efficient. I will keep working at figuring out why the center support won't line up. It did before so it should go back in.
I really appreciate you taking the time to help walk me through this rebuild Ben!

 

So I took it all apart, checked everything put it back together and it dropped right in and lines up first try. I made the mistake by soaking all my clutches at the same time so when I put the intermediate clutches in and was checking for clearance I'm not sure how accurate it will be now? I know I should have checked clearances dry but it was late at night and I gapped out LOL. So that being said I have .038 clearance. That's with the new heavy duty snap ring supplied with my Transgo kit which is supposed to help with stopping the lugs from braking off. The original snap ri g is .092 thick where as the new one is .096 so only a difference of .004
How much do you think the fluid soaked in the clutches are worth? .010??

 

I dont think they swell up that much, but on that one you kind of have what you have, are you using the wave plate there or not.

The soaking is so they actually grip without smoking right away

 

There wasn't a wave plate in the intermediate clutch when I took it apart?? There were two 0.0975 steels and one 0.100 in there and I replaced them with two new 0.0975 steels and one 0.0965 steel.

 

I find that the Fretting ring (number 59) was not used until late
1969, but you can use one with the later center support in the older
case. Or machine 40 mils off your old center support. I am pretty
sure all original clutch packs used a wavy plate. Bruce Roe

 

So I got it all together finally! I checked my input and output shaft end play and I ended up with 0.011 on the output (specs are .003-.019) and 0.012 on the input shaft (specs are 0.003-0.024). I ended up drilling both holes on the separator plate of the Transgo kit to 0.125 to start and did all the valve and accumulator mods. It's been quite the job but I've enjoyed learning and doing all the work myself. Here she is all ready to go with my new 9.5" torque converter from Jim Weise and my JW "the wheel" flexplate is on. Tomorrow it goes back in!

 

Looks nice, no left over parts

 

Thanks! Nope, I triple checked everything putting it back together making sure everything was in place and torqued to proper specs. I thank you again Ben for taking the time to aid me through this rebuild. I've learned alot and had fun doing it!

 

Hope it works as you plan

 

I hope so too lol! If I did everything right I should only have to open it up to drill the holes bigger. The new vacuum modulator is adjustable so I may be able to play with that a bit to fine tune my shifts?

 

That's not an accumulator valve, it's the vacuum modulator.

Accumulator are inside the tranny and help cushion shifts.

The modulator helps control when shifts occur. Nothing about the quality of the shift.

When driving normal,,,,,,,light throttle around town. The engine vacuum is higher, the high vacuum pulls on that piston in there and reduces load on it allowing early upshifts, by screwing that in your increasing the load causing later upshifts.

Reverse for in you want earlier

 

Yes you're right Ben, I edit my post to correct that. There's so many parts and names to remember lol

 

I wasnt trying to correct you in your posting, just wanted you to know what it does and why so you can help set your stuff the best you can.

I had ppl help me along the way, share info, and some I learned the hard and pricey way.....

 

So today is the day!! I got the trans in yesterday by myself but had to finish buttoning everything up today. I did the new trans install procedure and there's no leaks or wierd noises. My new flex plate and torque converter are spinning straight as an arrow! I took it for a few test drives around the block shifting gears and rechecked everything, all is good. I took it for a run down the hwy and everything seems good. That new 9.5" torque converter from Jim Weise really gets that big car moving. I'm going to do a bit more testing and see where all my shifts are at in both modes. How many miles do I have to put on the trans before I really push on ot hard?

 

It's either going to work or not, there isnt anything to really break in like a motor. If no major leaks and all gears are working you should be good to go

 

Ok good to know! For info purposes I have a Derale extra deep extra capacity pan and I've got 10 litres of fluid in the trans now and its reading at the full mark.What I've noticed in automatic mode my 1-2 shift is very early and short, almost no existant. It shifts at 1500-1800 rpm (20mph) and it's a quick little thud. My 2-3 shift happens at 3500rpm and is crisp. I'm going to try and adjust the shift timing with the vacuum modulator and see if that helps?