I put a new transmission on my 02 Cadillac dts had to take everything apart, including part of the frame, steering wheel, ect. i put everything back together like it was and turned it on, but now the car wont move, the dash lights shows that the car is on neutral even wen i shift to drive, reverse or even 1 2 3. i double checked everything two mechanics took ah good look at it and nothing. the car turns on and accelerates, but does not move when i put it on drive, and the dash light stays on neutral. and a message popped up saying my limit is 90 mph? someone give some feed back please

Cars & Trucks - Cadillac - DTS