I recently rebuilt my th400 and put everything new including rear band and pump with the tci pro kit with shift kit all new piston seals and new rear servo spring. Reverse does engage like it's transbraking and once gas is applied it moves with brake resistance in reverse. The forward gears seem to function and I was wondering if anyone had suggestions regarding this issue. I think it might be a rear band issue with pin clearance? Any thoughts would be greatly appreciated.

 

Are you using the transbrake while reversing? I know with that kit you are supposed to. And if the servo pin was the right length before the rebuild I would think it would still be ok.

 

hi thanks for your help, during breakdown it was not equipped with a transbrake on the vb and it was all stock and thats why i was perplexed on it acting like that. As far as for the pin i looked at it and it looked ok but i did not measure it. i guess the band is not engauging then?
thanks for you help

 

To be clear, I'm no expert.....but you may have a leak in the reverse circuit. Sounds like it's working....but for whatever reason isn't getting full pressure. Not trying to be a smart alec but did you put the servo gasket on the right way, as in grooved side down?

 

oh ok thanks and i will check when i drop the pan.

 

It's been a while since I have had time and I forgot to ask what side of the ridge on the rear servo gasket goes to the case? And I'm going to be pressure checking with a tool I bought because I'm thinking I have a bad valve body. What are the values ratings psi?
Thanks a bunch everyone.

 

The gasket can only go on one way. If the band were not applying, the engine would rev and it would move slowly if at all. If the band were on all the time, then reverse and 1st gear would work ok and it would bind as soon as 2nd gear tried to come on. Do the forward gears all work correctly? The problem you have is somewhere else, possible cross leaks.

 

It acts like there's a transbrake and with throttle it moves forward and reverse but with resistance like brake is on. I'm wondering if it's a valve body issue/failure because that was the only thing I did not completely tear down.

 

Sounds to me like the rear band is staying applied. I doubt that the valvebody somehow failed. It's likely something with that spring you installed, whatever it is....something is keeping the band applied. I also doubt that the servo pin is suddenly too long, if it was the correct length before the build.... it should still be the correct length.

 

I will pop the pan and check that pin length and engagement. The rear Servo spring was broke during tear down and I had to buy a new one maybe that's the problem. So with a brand new band I can see that you maybe right on it staying engaged. Is the servo .080 pressed into case movement?
Thanks for the help

 

For what ever reason I rolled the car 15ft forward and backward with engine power with it transbraking then it all went away and is now working fine. I think it could have been a stuck check ball that freed it self with operating it more than a few feet like I did before.
thanks for the help everyone.