Drivetrain What To Look For When Buying A Used Aod?

[webshot]

I am looking for a used AOD and I know there are no guarantees when doing this. But are there some outward things I can inspect for when looking at one? Also I am gonna try to tackle the install by myself. I have some mechanical skills but never tackled a tranny and most of my stuff is self taught or learn by watching others. Is this something a hobbyist garage mechanic can handle? Will I need special tools?

Any input appreciated. Oh yea the car is a 89 GT stock GT.

 

[David Pepiton]

no special tools but might want a friend or two if you don't have a trans jack. I've found removing the Motor mounts and using a cherry picker to hold engine and removing the headers really helps the exhaust on AOD transmissions is really tight plus the x pipe will need to be out to get the trans in anyways

as fare as inspection pull the tranny pan and look at the fluid.
look for cracks in the casting and so forth.
the best way would be to already have it installed in a vehicle but if thats not possible its kind of a crap shoot.

 

[95Vert383AOD]

What sucks is that any used AOD is going to be at least 20 years old. They weren't very great pieces in stock form either. Chances are you may be looking for a ticking time bomb.

 

[ratio411]

I will never again buy one that:
was obviously ran without a throttle cable, or maladjusted cable...
is not sealed up, including still holding the converter in place, and all holes carefully plugged...
does not have a pan and gasket securely in place...
I cannot remove pan and inspect the inside before buying it...
the moving parts inside do not move with hand pressure... (servos and pistons)
the fluid is totally gone, dirty, or contaminated with water... (or anything else)

Even after all of this, you could still end up with a boat anchor.
All of these things I have seen wrong, and the tranny didn't work.
Always fill the converter partially on a tranny that has sat, or you can burn up parts/pump before it primes.
Any servo, piston, or moving part that does not move by hand, will usually not move under operation. If they do happen to unstick, it is often after damage is done, or they will stick again over and over, never really working right again.
Don't forget to listen to your nose either. Bad smell, walk away. It's too easy to get a bad tranny to gamble.
Most of the trannys that I have got that didn't work, were bought from friends, and were either known to work before they were stored, or at least rumored to if the friend didn't know first hand. So make sure you deal in a way that you won't lose a friend if you get one this way.

 

[webshot]

thanks guys.... I appreciate the info. Any good write ups on tranny replacement you guys can link me to?

 

[ratio411]

Tip: For the top starter bolt, get a long extension for your 3/8 ratchet, and bring it in from the FRONT of the engine, between the engine mount and frame. You will have to see what lines up exactly... I forgot. But the extension routed through a specific opening in the mount set up lands the end of it directly on the top starter bolt. Then you just install ratchet and crank from the front of the engine bay. Easy cheezy. There is also a route through the k-member area to do the bottom bolt as well from the front of the engine, but I usually don't worry with that one as I have the car in the air anyway. If you were working with wheels on the ground though, that is a good one to know.

 

[2000xp8]

Have you considered a 5 speed swap?
In an old foxbody it will make you feel like you have a new car.

 

[webshot]

2000xp8, nah not really. Believe it or not I want to keep it a aod.

ratio411 you can do a tranny without jacking the car up? I ask because I am pricing tranny jacks right now.

 

[95Vert383AOD]

I love my manual valve body AOD. The AOD can be made stroooong.

 

[ratio411]

I couldn't do one without having the car up the in air, all 4 wheels.
(I suppose you could point the nose to the sky and just have 2 wheels up, but I wouldn't want to.)
I wouldn't want to do one without a tranny jack, but could I suppose.
You'll need the jack for the car, 4 stands, and if you so choose, the tranny jack.
If you don't get the car up on all 4, the tranny is very hard to get out. You still have to muscle it off the tranny jack to get it out from under the car. I use plywood or something I can slide the tranny on.

 

[ratio411]

The AOD is just like anything else... with enough cubic dollars, you can build it strong as you like.

 

[95Vert383AOD]

Yeah changing an AOD on the ground sucks....Thats for the young guys.

 

[webshot]

thanks guys, yea I am gonna do the jack stands and tranny jack route. I am gonna search around here and see if someone has done a walk through. Or maybe see about a chiltons.

 

[webshot]

Oh yea, are there any routine things I should do while I have the tranny out of the car? Like replace certain parts or anything like that?

 

[mikestang63]

I wouldn't buy a used AOD unless I saw it running and then was able to inspect it physically. Too many internal timebombs. If the last guy didn't have the TV cable adjusted correct, or did the 1D1 shuffle every shift, you bought a boat anchor. Unless you are in a real bind, it's better IMO to rebuild the one you have so you know whats in it.

 

[ratio411]

Yeah changing an AOD on the ground sucks....Thats for the young guys.

LoL!
I remember seeing a guy tunnel his yard under his parked car to swap a tranny.

 

[ratio411]

Oh yea, are there any routine things I should do while I have the tranny out of the car? Like replace certain parts or anything like that?

Replace the front and rear seals, new fluid, filter, and gasket.
The better pan gaskets are durable rubber, and some with metal anti-crush inserts around the bolt holes. Those can be reused several times. Most gaskets will have at least 2 holes cut smaller so the pan bolt gets stick in the hole. That is for you to have a way to hold the bolts up without needing more than 2 hands.

It's your preference, but I just make sure everything is spotless clean where the gasket seals, and go from there. If your surfaces are clean and flat, you shouldn't need RTV on a tranny pan.

Check the pan itself. Most of the time the bolt holes are 'dented' upward just a bit towards the tranny.
You need to take a small hammer and something flat to push the 'dimpled' bolt holes back to flat.
Then when you tighten the pan down, don't go tight enough with the bolts to dimple the pan much.
That will keep the pan gasket nice and dry. The dimples keep the area between the bolts from sealing well.

 

[pearlnotchback]

Yeah changing an AOD on the ground sucks....Thats for the young guys.

Ya I remember the days of laying down on a creeper and having my two buddies set the tranny on my chest and grab my feet and roll me up under the car. lol hey it worked

 

[gearheadboy]

Ya I remember the days of laying down on a creeper and having my two buddies set the tranny on my chest and grab my feet and roll me up under the car. lol hey it worked

I used to do that alot, but an AOD weighs a TON!

 

[twistedwankel]

I had a private mechanic with a backyard garaged lift replace my wife's 88GT AOD and he got the new one from a boneyard he trusted to get low miles pristine ones. Her's the OD gear blew out which was crazy expensive to have replaced in our low miles 88k car. So went with a used one instead as we got tired of the high rpm of 3rd gear on the hwy and it was alot cheaper going used than rebuilding.

The boneyard will guarantee replacement if it's bad but they won't compensate for labor....ouch.

Initially the new OD would occassionally hangup at low speeds as it sat around alot. Took the car on a road trip 200mi. to get everything hot and working again and it was fine after that. Sold the car a year later so don't know how long it lasted? If you are keeping anything for along time it's probably better to get a fresh rebuilt one with a warrantee. Or like the man said: "Get it built for more HP." If you're headed that way.

If a "known person" on this board wrecks their car and parts it out I wouldn't hesitate to buy their's even if it were packed on a crate and truck shipped.