When you put your car in reverse it cuts off?

This was a common problem on mid to late 80s' GM cars...The torque converter lock up clutch does not disengage and when you put the gearselector into drive the Torque converter clutch stops the motor.

The test for this problem is to put the drive wheels up in the air-put the car in gear and see if the motor kills. If not then the Torque converter clutch is stuck.. The simplest repair is to unplug the Torque converter plug on the outside of the transmission then the Torque converter clutch will usually disengage.

If you could tell me what make/model/year and motor that you have i can be more specific.

Hope that helps..

Good luck.