Tranmission Problems??

I'm more of a computer techie than car mechie so i need some expert advice. My '97 olds might be having transmission problems. The van shutters when i drive slow in reverse and shifts hard from 1st to 2nd gear. I brought it to a mechanic and he charged me $100 to change the fluid or filter or something but it didnt fix the problem. He said i might need to rebuild the engine ($700!!!!).
Any suggestions??

Get a second opinion about the engine. Im sure its the tranny. Did they replace the filter when they changed the fluid?

I personally have a hard time trusting most tranny shops stay away from the chains thyre there to make money off peoples ignorance. And anything related to a tranny is expensive.

To find my tranny shop I called around and explained the trouble and then went to the one with the most sensible response for an estimate. Then I get 2 more and go from there.

Oh by the way they can smell ignorance take someone that knows cars with you. Thats why my hubby gets me for all the vehicle tbls hes a computer geek too, knows little about cars.