Hey guys,

I went to start driving and breaking in my motor today finally when I had some transmission issues. The transmission is a 904 assembled by me, with a tranzact pro brake. The issue I was having was when engaged in reverse, I did not feel the trans shift with my foot on the brake, nor did I have reverse when I gave the car gas to move. I then proceeded to try all forward gears with my foot on the brake and all felt fine. Moving, 1st to 2nd shifted fine, then shifting to 3rd I felt nothing...no change in rpm, no shift feel...then I went to go let off the gas to come to the stop sign on my street and all of a sudden it felt like I engine braked the HELL outta the thing. Scared the crap outta me as the wheels almost locked up, so I put it back in first and drove it back around the corner home.

I am using a non low band apply valve body, and according to the service manual it looks like the most serious issues that are shared between both gears is the rear band (which is adjusted properly according to tranzact instructions for a used band which was 1-3/4 turns, but im going to pull the pan off to re-check), the front drum (which has been assembled by a professional, has the proper clearances, TCS multi return spring, and been air checked by me as well), and the rear/reverse servo. Now I do not have the stock reverse servo, it is a billet reverse servo as sold my mrandyj in the transmission section every month (which is a real nice piece btw). Now if I remember correctly, I installed it with the large spring that goes under the retaining ring, but no spring for the actual servo piston since it is supposed to be solid (although I will not know for sure until I pull the servo out). Here is a link to the part description if it helps
https://board.moparts.org/ubbthreads/showthreaded.php?Cat=0&Number=7692012&page=0&vc=1

Anyways, I am just about confused as [Edited by Moparts - Family Friendly Site - Keep it clean] with this thing since it seemed like it all went together properly...What even concerns me more though is not just that I didn't get third or reverse, but that when I let off the gas I was met with unpleasant whiplash from what seemed like the trans locking up in 3rd. My fluid level is good, trans fluid was not burnt or hot, and as I said the other areas of the transmission work well. I did notice when messing with the shift lever on the trans itself by hand that it feels almost like it doesn't engage reverse as well as the other gears, although it does engage (and third does as well). Only other thing I am thinking it might be is a valve body issue, but not sure what could be happening there if it is or how to diagnose if it is.

Anyways, any help you guys might have would be awesome...I was really planning to have this thing ready for the first race of my local series next weekend, but with this and a major job interview on Thursday I need to prepare for, it seems like that won't be happening. I am just about stumped here, and am really hoping it is an easy fix with just the pan off since I had to yank the trans and put it back in 4 days ago to fix a leak at the back of the block, and im not really in the mood to do that all over again if i dont have to.

Thanks fellas
Matthew

1 thing with regards to rev I ran a Tranzact pro brake for years and you do know for rev to work you have to push the trans brake button with shifter in rev or N.

I forgot to mention, I am running a blanket that I just thought of might be affecting the shift linkage [Edited by Moparts - Family Friendly Site - Keep it clean]!

I think the locking up in third is the shift pattern is reverse. So you actaully put the car back in first. With low band apply it will do some serious engine braking.

Leon

I had my first trans-brake VB Rev, band adj.@ 1 1/2 turns and it locked up solid when I let off the gas at the end of the 1/4....., not fun. might want to set that at 3 1/2 or 4.
just my experience .
Jim

Well I have been doing some searching on here and it seems like others have had issues with tranzact valve bodies locking up in 3rd gear or not even going in and locking up...I sure hope its not a vb issue

Again, if anyone has any experience with this, please chime in....I am going to go out and try to adjust the band, but I am not going to lie I am a little scared to shift it into 3rd now after what happened yesterday.

1 3/4 is the correct adjustment for a 904. joe told me u will hardly feel the 2-3 shift jack stands. how much line pressure do u have? i set mine to 180#. works perfect.

my 2-3 shift is firm(doesn't bang). is ur detent correct?

i tried different settings & 180# give me the best shifts.

on jackstands, i could barely feel the 2-3 shift as joe stated. i would give him a call. i would try another vb as a test. if it works fine, there could pressure leakage in ur new one.

if the rear band was holding all the time it would bind up hard as soon as it hits 2nd gear you would never make it to 3rd,and I have seen the rear band set any where from 1 1/2 to 3/12 and would work fine