Stuck in 1st gear AOD [Archive] - Classic Cougar Forums

: Stuck in 1st gear AOD

December 4th, 2007, 01:38 PM
First I could swear that this thing hates me.

So here's the background information about this transmission. It's out of an 87 mustang 5.0. The owner pulled the transmission because it was stuck in 1st gear. I bought it and rebuilt the entire thing myself. All new clutches and steels. I rebuilt the valve body too and put in a transgo shift kit. Anyway today I finally got the TV pressure adjusted and decided to go take it out and see what it would do. It goes into reverse just fine, neutral, and drive just fine. So I backed it out of the driveway, put it into drive and started to give it some gas. 1500rpm, 2000rpm, 2500rpm, 3000rpm, 3500rpm and it still won't shift out of 1st gear. I messed with the TV pressure to see if I could get anything out of it and I didn't get anything out of it.

So where should I start looking for the problem? :confused:

December 4th, 2007, 04:28 PM
It is very important to follow the recommendation on tightening order and torque specs for the valve body. I hope it is that easy...


December 4th, 2007, 05:19 PM
And other things that may be bad:

* Manual linkage is not properly selecting the gear (OD, D, L)
* Intermediate clutch pack is not applying due to seal problem
* VB has a stuck valve causing int clutch not to apply
* Clutches are already burnt up in 2nd from driving it with bad TV setting

Did you set up an air-test plate on the tranny and check operation before attaching the valve body? I won't do an AOD without a full air-test. It is without a doubt the most difficult of small-block trannies and everything has to be cross-checked.

Glad to hear you got the TV setting resolved. :)

December 4th, 2007, 06:07 PM
Oh boy. I know that I fallowed the tightening sequence on the valve body to the correct specs and order, so I know that, that is not the problem.

When I rebuilt the clutch packs I had to take them down to my local mechanic to have some of the parts installed because I didn't have the correct seal installing tools. When the packs were down there I had them perform the air test on each pack to make sure that they were engaging. All of them passed, so I'm pretty sure that, that isn't the problem.

I'm pretty sure that the manual linkage is all hooked up right, but I'll got out and double check that.

The valve body is what leaning towards. The valve body at some point had, had a shift kit put into it. Some of the plugs where different looking than the ones shown in the pictures of my manual and shift kit pictures as well.

Also when looking around on the internet and looking in my rebuild manual it said that it could be the governor or a servo adjustment. I never replaced the governor and I didn't mess with any of the adjustment screws on the transmission that would have moved the servos.

Or one other thought I have. Since the guy I bought it from said that it was stuck in first gear, would that lead more towards a messed up servo? I'm just taking a guess here, but the fact that it was stuck then and is stuck now makes me wonder if it's because the servo for the 2nd gear is messed up.

December 5th, 2007, 12:28 AM
AOD doesn't have a 2nd servo -- it uses the piston that mounts to the front pump. You can't air test that on a bench because it'll blow the piston right out of the pump and you have to start over.

2nd has to be tested on a fully assembled (minus valve body) tranny.

You can pull your VB and air test it assuming you get a good seal at the apply point. Before buying the proper AOD test plate, I made my own which was a pain but it worked.

AODs work great when *everything* is perfect. One slip up and they'll fight you back hard.

December 5th, 2007, 02:44 AM
You can put the govenor on backwards and think that it is right, but it wouldnt shift out of first gear. i would check that. its an easy mistake. when you take it off, the holes in the gov need to be closest to the case and not the end of the tail shaft. also while you have it off clean it really good so you can eliminate it as a problem or keep from having to take it off again because the transmission is shifting late. Hope this helps.