I have a 91 Dodge Spirit with a 3.0 V6; 4 speed auto transmision.
The body code tag says it is a AADX41. What kind of tranny is it? Where can I find a complete tear down and rebuild manual??

I don't know what number the overdrive tranny is. If I were you, though, I'd look for a good 3-speed. Those things go forever if you use the right fluid, where on the other hand you're really lucky if you can baby a 4-speed long enough to get 125,000 miles out of it. The difference in fuel mileage is negligible, and I would assume that 3-speeds would be easier to come by (I have an '87 Lancer and my dad has a '96 Caravan- both 3-speeds). I've seen too many overdrive trannys croak for no reason that I wouldn't rebuild one if I could replace it.

it's an A604.
Tough luck.
Ironman502's idea is better. You'll find the three speed trans in any lebaron, daytona, spirit or acclaim from 89-92 with the 3.0 in it.
it's a bolt in swap more or less. use the plugs from the new trans and swap over the wiring...
Or do what everybody else does and send it, along with the bad A604, to the boneyard.

Or pay someone $1200.00 bucks for another one that'll only last another 50k miles if you're lucky.

Slantsixness