Originally Posted by
CraigMBA
Your belt tunnels need to be changed. All the problems people have had with belts and idlers come down to the belt tunnels getting warped, which misaligns the belt, which randomly causes the belt to come off. One hard yard dart is enough.
If you search this thread, you will find many other users over the past six months who have had this problem.
It is also why so many of us have gone to the chassis brace, which (IMO) is misnamed. It's a belt tension stablity device. Chassis under compression with the chassis brace:
Chassis under compression, one end of chassis brace removed:
Also make sure that your motor mount is properly seated in the groove and didn't slip out when messing around with the rear diff. The only time I had belt problems was due to that. A tell-tale sign is that you will have a small gap on the rear of the belt tunnel and a small groove being worn down the center of the spur from the pinon being a little off.