Front pinion bearing - too tight?

A local shop replaced front pinion seal back in Feb. As of about a month ago a whine started, sounds like it's coming from front. I replaced front wheel bearings and it's still there. I removed front prop shaft and recorded a video turning front pinion flange. Is this normal?

2001 Suburban - 4x4 - @ 265K miles :smile:



Well-Known Member
OMG, that pinion bearing is toast! It was tightened way too much!

It should spin over with just a simple twist of the wrist. Normally you can't tell on a video how much pressure someone is applying, but I can see that it is taking way more effort to turn the pinion yoke. And that noise, should be just a whisper whir as it turns, and it should turn smooth, not feel like it has lumps in the rotation.

I accidentally over tightened a pinion nut on my own vehicle when I did a pinion seal. On my drive home the pinion bearing seized and the rear wheels locked up and I skidded through an intersection. That was my first pinion seal job and I'm glad it was on my own car. It's not very complicated to replace a pinion seal, BUT, you CANNOT make the one mistake of over tightening the nut. Their are simple steps you can take to prevent this from happening, they didn't follow them.

And, they may say it's just coincidence that this happened, no way! If the bearing failed it would normally be very loose, your pinion is very tight.

Bad job, go back and have a senior guy do it or better yet go to a driveline shop that specializes in diff service.
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Long story. Our encoder motor went out on the tcase and I didn't have time to do myself with full on winter in the driveway, so we took it to a transmission specialist. They also fixed and replaced the front/rear pinion seals since they were leaking. Sounded fine for the 1st couple months until the rear end went out. Sounded very similar to front now, except sound was in the back. Luckily we had a friend with a whole rear from a junked avalanche that we swapped in. Problem solved. The rear pinion flange wasn't tight like in video. Considering the high miles I chalked this up to just a coincidence.

My question is, how do you approach the shop when the vehicle has over 250k miles?


Well-Known Member
My question is, how do you approach the shop when the vehicle has over 250k miles?
First off if this is the type of automotive work that they do, they will KNOW that this can only happen because the pinon nut was tightened too much. Unlike the rear axle this only spins when you have in 4wd, so that's why it lasted this long.
Second, you need to go in and be confident that you know that this was, IS, their fault. If you are timid they will try to buffalo you. Don't go in roaring in their face, but be respectful and explain that you are aware that if the pinion nut has been tightened too much the bearing will be destroyed. Don't back down.

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