1969 Oldsmobile Cutlass

What were the symptoms before the problem started

The symptoms were transmission leaking at rear seal, low transmission fluid, and dragging (felt like the car wasn't taking off as usual). And my father didn't let the car warm up either.
Also, if you can figure out the answer, do you know what the price would be to fix the problem?

Sounds like due to low trans fluid the the pressure in the trans was low and allows the trans to slip and wear out the steel and fiber discs causing it to seam like its not shifting into gear. But in actually it is. Just slipping baddly. What city and state do you live in

Tyler, Texas

I used to live in Arlington but now I live in fort myers florida or id just come to you remove the trans and rebuild it with high proformance parts. If you plan to soop it up. Theres an aamco transmissions shop or you can locate a used transmission from a salvage yard.

Well, I can do that from a salvage yard but I don't know what kind of Automatic Transmission to look for? Or if I want to buy a new one. Does it matter of what kind of engine size it is? So, can you help me... it's a 1969 Oldsmobile Cutlass Supreme 4dr. Sedan, with a 350 Rocket engine, 2 barrel carb.

Yea its gotta be a olsmobile bellhousing. And its a turbo 350