Hi, Our 1996 xjr automatic has today decided that life will be happier without 4th gear! We had only been driving about 10 minutes and were slowly accelerating from 60 to 80kph. My wife exclaimed as there was a thump, that she thought was a car hitting us from behind. Then there was nothing…except the rev counter rising…because it was as though we were in neutral! A transmission fault showed on the dash immediately. I changed back to third gear and we were back in action. Shortly afterward I stopped the car, turned off the ignition and restarted the engine. The fault light disappeared…but the problem didn’t.
The transmission is full and the fluid looks and smells ok. All the above happened in normal mode. Everything else is perfect. Sport mode works fine, as O/D is locked out and kick-down is also good. My simple OBD plug in connection to mobile shows no errors.
Any ideas?
The TCM will likely have DTCs stored for fault diagnosis. Find someone that can read the GM gearbox codes. (WDS, IDS, AutoLogic etc.)
bob
Motorcarman is correct
That’s transmission is bullet proof
It might be a blip or the harness is loose or broke to the computer or sensor
I do remember mmmmany years ago that someone had the switch on the console failed causing the same effect
Good luck
Gtjoey2324