So when I am driving along and the vehicle is in top gear and I begin to go up a hill and the car needs to downshift to maintain the speed it begins to jerk around like it is having trouble downshifting. Also sometimes when sitting at a red light or stop sign the vehicle jerks a little. It will sometimes also have trouble taking off from a stop when I accelerate quickly; it is again a little jerky. I took it to the shop and they said there are no ?codes? on the transmission and they could not replicate the jerking when they took it out. It is a 2002 mercury sable LS with about 82000 miles on it. Anybody have any ideas what it may be so I can suggest it to the mechanic?