1996 Buick Riviera

Transmission problem
1996 Buick Riviera 6 cyl Two Wheel Drive Automatic 160234 miles

Hi, I have a 1996 buick riviera and when I got it started and put it in gear it took off very slow and did not change gears. So I put a used trans in it with very low miles (under 70,000) and it did the same thing as the trans that I took out. It takesoff very slow before it pickup speed and it does not shift gears. Can you please help me because I know its not the trans, could it be a sensor or solenoid?
August 11, 2009.

Trans is electronically shifted. You need a scan tool to watch input speed and shift soliniod operation. Could be a quad driver in the ecm also. God luck.

Car wizard
Aug 11, 2009.