Hello I have a Jaguar Xjl 2015 I got a used transmission which had just 26000km on it but After installation car is not able to go in reverse it’s going in front smooth but back gear is not working my mechanic tried with the TCM came with transmission but it worked and then he used the old TCM in starting and moving car ahead but not in back and idea what’s wrong here?

 

Sorry The new TcM did not helped and the Old TCM helped In starting and moving car ahead but facing problem in back gear.