I have noticed that at highway speeds - like 65-80 - my differential is starting to make more noise. Last time I had the rear end apart was around 30K to replace the pinion bearing. At that time the gear tolerances were right in the middle of the specifications...before I started the work and the exact same when I was all done. Now the car has about 57K on it. Is it possible that I may now have out of spec tolerances from wear that can be resolved with shim adjustments or am I wasting my time redoing this work again trying to eliminate some of the whine?