I have a TE Altera 3.0l auto wag. which has started a violent jerk when upshifting from 2nd to 3rd. I have reset the TCU and it goes ok for about 2 days, then the problem starts again. It has done 136K. Should I flush the trans, or is it something else- e.g. faulty TCU.

Have a full power flush done and see how you go,

I had the same problem on my first (third gen) magna. Lucky I had the car in warranty. Would have cost me around 1500 to fix. Somthimg to do with the computer.

check ur ATF (in the engine bay u will see a dipstick with ATF ontop of it) if its black/brown and smells burnt then get a tranny flush (a proper one, which they flush the torque converter) and see how it goes