I am trying to put a new(to me) tranny in and got one from a dismantaling shop and mine is Ao4d or whatever cant member if the 4 is before or after the o but anyways!... The new one has the number 56 on it and mine says 37... would it still work?

 

Your best bet for the correct answer is probably gonna be up in the Bronco thread. Are the trannies both from the same year vehicle or is one of them older/ newer than the other?
-Chris

 

Mine is an 85 and this one is for a 90. But it looks like its an upgraded one. as in not the stock 90 as is that it is still very clean.

 

Ouch, those were the years that had a lot of changes. My guess is the tranny stock to the 85 is the old style where engine vacuum and throttle position controlled the shifting and the lock-up torque converter. By 1990 the tranny had changed with an separate "engine control box" commanding the shifting. Sometime around then the ECO was incorporated into the computer.

There are work-arounds, but you need a special electrical harness for the transmission. Check to see if the two trannys have exactly the same wires, and connectors to insure they are compatible.

I know that if you drive it without the correct lockout you can ruin the torque converter in 50 miles or so.

I am a reasonable shade-tree mechanic and I wouldn't attempt what you are doing without some skilled guidance - even better, someone to help that had made this swap before. I strongly urge you to ask a more knowledgeable person what is needed.

You need to know for sure what tranny you had, and which one you are trying to install.

Sorry, wish I could be more help.

 

^^^Agreed....its gonna be a tough one,
Your gonna need more experienced input for sure...Im gonna hazard a guess and say that it may not...if your old one is an auto with over drive and the new one isnt over drive. You might run into compatability issues with the computers and such that Clint mentioned.
Good luck and sorry I cant be more help either,
-Chris