UPDATE: We continued to have issues with noise in our differential even after Arizona Differential serviced and inspected our differential and told us the ring and pinion looked good with normal wear. We took our truck to the dealer for a diagnostic and they discovered the ring and pinion had excessive wear and backlash was on high side of acceptable tolerances. They also told us whoever serviced the differential last (Arizona Differential) used the wrong gear oil and WAY overfilled which caused the oil to foam. So because they could not diagnose the initial problem and used wrong oil and overfilled during their service - I wont be back myself or recommend them.