Most times it is the opposite side bearing from the direction the vehicle is being turned. But not 100%, I've been burned before by that. If the truck has front coil springs jack the front end off the ground. Rotate the wheel with one hand while grasping the coil spring with the other hand. The coil spring will resonate in on the side with the bad bearing.
Doug
I know what you mean Doug as I have been fooled before on that. I always put the car in the air and run the wheels while putting my mechanics ears up to each hub and I can usually tell very easy for sure like that. Ron
