This is What Happens When Your Pinion Preload Loosens Up!
It’s not that hard to install a ring gear and pinion in the rearend of your car or truck, but installing it correctly is a bit of an art form, and as you can see in this video, when things get out of adjustment, the noises that you’ll hear are awful.
I can’t do it correctly and know many capable mechanics who often “miss” when setting the gears’ backlash and have this same whining noise come from their housing. However, in this clip, the settings are right, but the pinion itself has loosened, causing the roaring whine to present itself upon deceleration, a common issue among aftermarket rear gear sets that aren’t installed perfectly.
As you’ll see in the captions in this video, all that was needed for the pinion itself to be tightened back down for the whining to cease, and the truck has another quiet 40,000 miles on it since the repair.