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68c10airstream · 11-12-2017, 10:30 PM

Pinion bearings spin about 3 1/2 times wheel speed (3.50 axle ratio example) so the noise turns into a high frequency noise quickly. Keep an eye on u joint/driveline angles condition and layout. As a past gmc dealer mechanic i replaced a pinion bearing a second time after an earlier warranty claim (both times pinion bearing issues) and found a rear u joint that had a rough spot. Obviously this was in a stock application. Good luck.

11-12-2017, 10:30 PM	#2
68c10airstream Registered User Join Date: Mar 2013 Location: Marquette michigan Posts: 828	Re: why. pinion ratcheting sound ? Pinion bearings spin about 3 1/2 times wheel speed (3.50 axle ratio example) so the noise turns into a high frequency noise quickly. Keep an eye on u joint/driveline angles condition and layout. As a past gmc dealer mechanic i replaced a pinion bearing a second time after an earlier warranty claim (both times pinion bearing issues) and found a rear u joint that had a rough spot. Obviously this was in a stock application. Good luck.