Put 04 tranny in 02 Impala

You may have to change the transmission control unit.

You might be stuck in limp mode, were it won't shift out of 2nd gear, I don't know right know if this is a feature in the 02 Impala but will check are you getting any trouble lights like check engine or anything. Bye the way limp mode on some vehicles just allows you to get to a repair facility, hence limp....

It did start shifting through all gears(even overdrive) with some checking and filling the next morning. It has not wanted to shift a couple times since but needs upper engine mounst too, so I haven't been able to really test it well. Had a transmission manufacturer code too. Would the control unit from the other tranny help? The pins weren't the same on the connection.

change the tcm and the shift solenoid also the screen u should be good to go.