I have a 4l60e that doesn't seem to have 3rd or 4th. When I drive it shifts in to first fine and takes a while to shift into second, but it only shifts into second when tcm says it is shifting into 4th. According to the speed and rpm it is shifting into second though. I built the harness and checked all the wires to make sure the pinout is correct. It isn't throwing any codes and I'm thinking its the transmission, but what i don't understand is why when it is shifting into second it says 4th. Any and all help will be appreciated.