Ideal pinion angle is 1°-3° in stock applications; this is the guideline we’ve always used. We’ve had a few customers report a driveline vibration around 70mph when under power from the rear driveline. All have provided specs withing the 1°-3° range. We brought an affected vehicle into the shop and installed these 2° pinion shims which alleviated the issue.

The end pinion measurement on the two tested vehicles was 4° and 5°; both were perfectly smooth under power at all speeds. This caused us to toss the accepted 1°-3° spec out the window accepting the higher figure for lifted applications; after all, you can’t argue with results!