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Discussion Starter #1
We are having trouble with the FMVB in my th400. Whos VB are you guys running? Are you happy? We/I like the engine braking in all gears.

Ours now has a long ~2sec delay from 1st to second. Also last time out I smoked 3rd and Rev, not sure how as I never really use either. (3rd for when I'm cruising and Reverse like most people not under load or throttle). Trans guy seems to think that its an adjustment or linkage problem. I run the (like most) Art Carr shifter, and the detents from the inside of the tranny dictate where the shifter stays. The gates just really only limit the throw. I always adjust the sifters in multiple ranges.

We have broken 3 cases (other unrelated stupid chassis builder problems :shaking:) a rear output and now a smoked 3rd and Rev. Trans has held up pretty good other wise never really had trans problems that were not my fault. Billet 11" converter 2500 stall. 496, 11:1 BBC ~650 HP.

Thanks Jack.

Oh I need it yesterday....
 

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Hey Jack, we met at Jump Champs. I'm the guy who had the 4800 car out there.

I've had similar issues to you in the past. To answer your first question, I'm running a TCI full manual, reverse, VB. It's treated me well and is probably the simplest way to build a 400.

For your issues, there are obviously a ton of ways for the trans to fail. However, your 3rd and Rev. problem is all too familiar for me. Last January I lost 3rd and Reverse right before KOH EMC. The issue ended up being that whoever built the trans before me forgot a simple simple thing. You must have relief check-balls on your direct drum piston OR drum. It's possible you have a drum with no check ball and a piston with no check ball. Basically your clutches always have some pressure on them because they have no real way to bleed. Hence, you smoke the hell out of the clutch pack.

If you have a trans builder, I'd see if you could get your hands on that drum and see if it's got a checkball. It could also be plugged.

The 1-2 shift is another issue all together IMO. Let me scratch my head on that one. Does your trans run a modulator? Or does your FMVB eliminate that? How do the intermediate sprag and races look? There are a handful of ways to go there...

Here's a pic of how badly wrecked the direct drum clutch pack was. The steels literally welded themselves together.
 

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I have the TCI with the 1-2 gear engine braking option, mated to an AC shifter. Both have been trouble-free for years and I definitely have NOT experienced any shift delays.
 

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Who builds your transmissions Jack?
 

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Discussion Starter #6 (Edited)
Brad at Trans-Action. I know he has build a bunch of U4 trans including the spec cars and other higher end stuff.

Yes the clutches and steels were toast, with nothing else wrong. They are thinking that it may be something with the shifter detents or position. They replaced the shifting paw (dial saw blade thingy) and the spring roller. Its all together now. The converter got sent out, cut open, cleaned and re welded together. We are just waiting for a valvebody.

Edit:Looks like it might of been a TCI VB.

I do not believe there is a modulator in there as its Full Manual.

So the question is should I get another TCI (Assuming that's what was in there now) part # 221201 ~ $245.
Or a Culhane billet one for $540....
 

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4531 had a th400 VB go bad this year. Bad timing , normal trans builder was out of the country so dad had what we thought was a good company rebuild the trans for the U4 nationals. Trans went out again before the race was finished. Sent it back to reputable trans company and that's when they figured out the VB was bad. The right guy has the trans now and I'm confident he will have it right for dad.
 

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Discussion Starter #8
4531 had a th400 VB go bad this year. Bad timing , normal trans builder was out of the country so dad had what we thought was a good company rebuild the trans for the U4 nationals. Trans went out again before the race was finished. Sent it back to reputable trans company and that's when they figured out the VB was bad. The right guy has the trans now and I'm confident he will have it right for dad.
If you don't mind can you go into detail as to what was bad with the VB?
 

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If you don't mind can you go into detail as to what was bad with the VB?
I can't actually. What ever the problem with it was caused it to have low line pressure all the time, and almost completely loose line pressure when shifting. With about an hour run time at the Reno finals it smoked all the friction parts including the drums. Dad went to a constant pressure reverse manual VB for the replacement. What had been in it for 3 full seasons was a regular shift pattern manual VB with no compression braking.
 

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Brad at Trans-Action. I know he has build a bunch of U4 trans including the spec cars and other higher end stuff.

Yes the clutches and steels were toast, with nothing else wrong. They are thinking that it may be something with the shifter detents or position. They replaced the shifting paw (dial saw blade thingy) and the spring roller. Its all together now. The converter got sent out, cut open, cleaned and re welded together. We are just waiting for a valvebody.
I don't know. I'd be really weary of this whole thing.

In your first post you said this:

Also last time out I smoked 3rd and Rev, not sure how as I never really use either. (3rd for when I'm cruising and Reverse like most people not under load or throttle). Trans guy seems to think that its an adjustment or linkage problem. I run the (like most) Art Carr shifter, and the detents from the inside of the tranny dictate where the shifter stays. The gates just really only limit the throw. I always adjust the sifters in multiple ranges.
Maybe I'm just a skeptic, but it is so similar to the issue I had that I'm worried your trans guy is A) clueless to this issue, B) not telling you the whole story, or C) I'm barking up the wrong tree and he knows what he's doing. Like I said before, I'd want proof that the direct drum, or piston had a CHECK BALL in one. And it wasn't clogged with shit.

The direct clutch is only engaged in 3rd and Reverse. If that drum doesn't have a check ball, it will hold some residual pressure and drag in 1st and 2nd.... the only gears you admittedly drive in... and eventually burn up.

Just playing devil's advocate over here.

Direct Drum w/ checkball


Direct Drum piston w/checkball
 

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Discussion Starter #11
The directions with the TCI kit says to discard the seal lips on the direct drum and replace the springs. Set a clutch clearance .050-.070" and to discard the rings from the reverse accumulator and install a release spring.

There is just one check ball to be used looks to be near the band piston.

http://news.compperformance.com/Instructions/221201.pdf

I ordered another TCI VB and it will be here tomorrow. I will talk to the builder and make sure all the steps have been taken. Even if they have to pull the trans apart in front of me.
 

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Discussion Starter #12
Just talked to a guy at TCI. I guess if you engine brake in 1st it spins the shit out of the direct drum and burns it up. Says in the instructions not to shift into 1st above 15mph. I had to call and ask why. As we all know we downshift into first all the time at high RPM's, at least I do while racing....
 

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Just talked to a guy at TCI. I guess if you engine brake in 1st it spins the shit out of the direct drum and burns it up. Says in the instructions not to shift into 1st above 15mph. I had to call and ask why. As we all know we downshift into first all the time at high RPM's, at least I do while racing....
Got it. This actually makes a ton of sense. I've read up on guys drilling .050 to .063 bleed holes in the drum to allow more bleed as to reduce the likelihood of centrifugal lock up/burn up of the clutches.

Good to know.
 

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I burned up a TCI rmvb just from loading/unloading on trailer. My trans guy suggested transgo kit in a stock th400 vb and its so much better! He mentioned what was touched on here earlier about direct drum and residual pressure or something but he lost me a bit as he's built th400s for 30 years.

Just food for thought....

Sent from my LG-H910 using Tapatalk
 

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Discussion Starter #16
I burned up a TCI rmvb just from loading/unloading on trailer. My trans guy suggested transgo kit in a stock th400 vb and its so much better! He mentioned what was touched on here earlier about direct drum and residual pressure or something but he lost me a bit as he's built th400s for 30 years.

Just food for thought....

Sent from my LG-H910 using Tapatalk
What do you mean loading/unloading? That scares me... I just finished installing everything...
 

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Discussion Starter #17

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Don't freak out, lots of people run them without issue it seems.

Mine died after backing off the trailer crooked and hanging the 14bolt, then lighting the tires in reverse. After that, no reverse off third. Tear down showed a cooked band but good clutches. Something about the way pressure is applied in reverse was the culprit if I remember.

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Ok so how do you like the new valve body? I am looking at the same one.

Also Jimmy's now offers their own billet RMVB, I was quoted 420 for the kit. Has anybody installed one?
 
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