trans/rear combo

where can i find out which auto trans and what size rear end my car has?
this is something i have been wondering about, but all i get online is replacement part results.

This link has the most comprehensive information I've found online about Torqueflite transmissions.
http://www.allpar.com/mopar/torqueflite.html

For the rear end, measure the axle tube diameter. If it is less than 3", you have a 7-1/4". If it is 3", and there is a cover on the back of the differential housing, then it is a 8-1/4". If the is no cover on the back of the diff housing, then it is a 8-3/4".

If its all original I would guess it has a 904 trans and a 8 1/4 rear.

You should be a 904 trans unless someone changed it. The rear is either going to be an 8-1/4 or a 7-1/4. If you sneeze at the rear and it breaks its a 7-1/4.

i romp on it pretty good sometimes, and all i get is a roar, sometimes squealing tires, but never a broken ass...
so i guess its not a 7 1/4...
and im pretty sure it is all original, the guy i bought it from didnt tell me he had a new one put in, and he bought it from a kid who's grandma had died and he was just trying to get rid of it, so i think im 3rd owner...

Its most likly a 904 trans and ether a 7 1/4 ora 8 1/4,youd be surprized the 7 1/4 can hold its own mine did pretty good in my car i never broke it but ya my gears where only 2.73's so that didnt help the hurt and the tire was only like 4 inchs wide :scratch:

If the rear end cover is taller than it is wide, then its a 7 1/4. The 8 1/4 is almost round but a little shorter than wide.