Freshly Rebuilt TH400 issues.

[86Peter454]

No real struggle. No more than I would have expected to put them together.

I checked that the pistons would apply but not wether they leaked or not.

 

[crazy4offroad]

What about the valve body? Did you thoroughly go through it and make sure all the valves were free-moving? I installed one spring backward in my valve body (it had a large end and a small end) and ended up smoking the clutches in my direct clutch pack.

 

[crazy4offroad]

Re-read your 1st post, the fact 1st is slipping and reverse is fine eliminates the piston seals as the culprit. Hopefully it is just a sticking valve in the valve body. It will be the easiest thing to go through and make sure everything is 100%.

 

[86Peter454]

Alright. I checked most the valves but it's possible one is sticking I had one that was pretty tight but I kinda clearenced it to make it better.

 

[86Peter454]

Any other thoughts? Stuff to try to diagnose this?

 

[86Peter454]

okay guys i did some more driving and i took some videos that turned out to be less helpful than id hoped lol.

so it seems at times it will actually not slip or not seem to slip really bad.

but the truck is making this sound from time to time. at this point it seems to happen mostly when shifting from 1st to 2nd.

has not happened to me from 2nd to 3rd.

one thing i noticed is when i first take it out it seems fine. then i shift through the gears come to a stop pull it back into second the pressure gauge doesnt change. pull down from 2nd to first the gauge 0s out then comes back up to pressure.

any idea what that could mean?

any help is much appreciated. here are the videos.

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the squeek sound happens in first some times and if i get into it a bit and shift to second it happens most the time.

i will say i had some water or something come out the vent on the top of the case. (i know this because there is a hole in the floor board right above the vent lol)

i assume that is sorta normal i didint even know that was a vent hole.

thanks guys hope we can get this all figured out.

 

[HotRodPC]

Those pressures actually seem to be a bit high. Could be due to the boost valve or the dual feeding making those normal readings. How about check balls??? Did you forget any or leave any out? I'm fairly certain you could have left 1 or 2 out but are you certain you left the correct ones out? With all those mods, I'd be at a loss to even start making educated guesses. That screeching noise isn't good though for sure. The couple of times I've heard of those issues, it turned out to be a bleed somewhere where that transmission is trying to apply pistons or servos that it shouldn't be.

 

[86Peter454]

Yea I certainly left out check balls the transmission had a kit in it and only had 5 balls. That's all I put in it. I'm fairly certain they are in the right place.

Yea I thought they where high too. I did the boost calve mod to let the pressure bleed off. Maybe I didn't grind it far enough to let it bleed more? But I feel like too much pressure would still apply pistons.

I'm wondering if when I shift it down to 2nd then 1st maybe it isn't fully coming out of 2nd or maybe not fully out of 3rd or something? And that's why it slips when taking off? Could 1st and 2nd or 3rd apply at the same time?

 

[HotRodPC]

Yea I certainly left out check balls the transmission had a kit in it and only had 5 balls. That's all I put in it. I'm fairly certain they are in the right place.

Yea I thought they where high too. I did the boost calve mod to let the pressure bleed off. Maybe I didn't grind it far enough to let it bleed more? But I feel like too much pressure would still apply pistons.

I'm wondering if when I shift it down to 2nd then 1st maybe it isn't fully coming out of 2nd or maybe not fully out of 3rd or something? And that's why it slips when taking off? Could 1st and 2nd or 3rd apply at the same time?

They can sure be trying to apply at the same time if there is a bleed somewhere. So let's say you need a dirct clutch pack and forward clutch applied to make 3rd gear, but the intermediate band is being applied holding the forward drum to make 2nd gear, then you have a 2 gear binding situation. A situation like that very well is what cause screeching in the transmission.

Need to get it figured out quick though. With the slippage and the screeching I'm thinking this is going to be a very short lived build that eventually gets aborted and have to start all over. I've just never seen the need to over modify a Th400 so I never have, past tossing away a check ball and making a couple holes bigger in the separator plate is about all I've done to one to firm up the shifts.

 

[86Peter454]

yea the case had damage around the governor so i decided to delete it and just go full manual. i also dual fed as i was recommended to do so by some people here so i figured wile i was in the trans i would dual feed it.

upgraded the druim so i could use the 34 sprag to make it a bit stronger.

but your right im pretty sure it will be short lived.

i pulled the valve body out today to find out if something was sticking or not. look at the ammount of flakes in this thing.

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to the point i wonder if the screeching sound is just second gear applying and the frictions no longer having material and just being metal disks.

so i took the valve body out and took all the valves out and cleaned everything up as much as i could.

i did find one valve to have possibly been put in wrong it was not the 1-2 it was this valve (not sure what it does)

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though according to my video i didnt even take that valve out. its got a spring on it and i kinda flug it when taking it out. (not like across the room or anything just a came out with more power than expected.)so its possible that valve was just fine.

i did check that everything was clean and moving freely as it should.

was not able to test it though because i need a new gasket and hell may even get a new filter while im at it.

so probably wont be till next weekend till i can test it. if anyone has any other thoughts especially while the pan is off im all ears.

 

[HotRodPC]

Not sure what format the pics are, but I don't see them.

So how was this damage in the governor area? Are you sure you don't have a bleed in any governor passages???

 

[86Peter454]

i redid the images hopefully you can see them now.

basically the governor had scored up the trans housing.

i removed the governor tubes and plugged then. then drilled a hole in the valve body here

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this was from this site. http://www.crankshaftcoalition.com/wiki/TH400_rebuild_tech

thats to loop the governor lines when plugging them.

 

[crazy4offroad]

That grey mud in the filter is clutch disk material. Something similar happened to me and i smoked the directs in a matter of 5 minutes, all because one spring was installed backward in the valve body. I hate it for ya but you're going to have to tear it down again, as well as flush out your cooler and torque converter.

 

[86Peter454]

dope lol.

still gonna try to fix this problem first. no point in tearing it down replacing clutches just to burn them out again.

 

[HotRodPC]

And there was no mention of punching any holes in the valve body gasket??? I know for Th350's I keep a paper punch in my trans tools drawer. This is for vb gasket mods. When I'd get a transmission that had a Trans Go, B&M or Hurst kit in it already, I never bought new any new special gaskets for the transfer plate which is what did the dual feeding. I just used a paper punch and punch 2 holes in the gaskets that came with the rebuild kit. Worked like a charm everytime. So, just asking if you did any mods to the paper gaskets like to match opened up holes in the seperator plate etc. And you followed all the other steps? And certain where you plugged off holes that the holes stays plugged?