Ok, Sorry I was in a hurry earlier. It is a rebuilt TH-350 trans. The jerking takes place around 20 mphr and lower. I do not have to apply the brakes for this to happen.It just starts doing it around this speed, I can ste3p on the gas and it stops instantly. There is no slip in the transmission at all and other than this the car is running fine. Although it does seem to be idling a little rough at the stop lights.