rhjokie2

My new 2014 GMC Sierra Z71 also had a vibration at about 35-45 and 68-75. After numerous wheel balancing, re-indexing, front axle replacements, both drive shaft replacements, the dealer finally inspected the ring/pinon gears in the rear differential and discovered the teeth were not the same length (varied from .003 to .085). The dealer replaced the rear differential and this seemed to solve the problem, although not sure. I have the p/u in storage while we travel in our motorhome.