Glad you had a good experience. I went from Motive 3.73's to FRPP 3.73's along with some other work and all gear whine is gone. AZ Diff set me up good. I think my motive gears werent matched up correctly from the manufacture.Sorry guys but did you know that Motive is the one that makes the FRPP's gears?? I have always chosen to buy and install Motive since they take the guess work out of pinion depth. When they sale the Ford Racing ones they don't put the depth on the pinion and its up to you to find it. I have in stall a number on Motive gears and never had them whine.Very nice! The frpp gears are very nice gears.