I'm getting a high pitched squeal when I punch it. It's not there when I am driving at a constant speed but when I really goose it on the straightaway it does it. It doesn't do it when it isn't under a load either. On a stand with the wheels free it's fine.

I thought maybe it was the belt in the front but it sounds more in the rear. I checked the spur and the pinion and both seem fine. The motor is nice and tight.

It could be the motor, but I can't think of what that would be.

Any suggestions?