I have a 2013 Mustang 3.7L and Ford just replaced my pinion bearing among a few other things. I will have more details later today when I pick the car up. The dealership said they found metal shavings in the differential.

I've driven a few hundred miles on this bad pinion. My back tires wobbled back and forth and there was a loud grinding noise

Could something like this damage or degrade the gears or other parts?
What else should typically be replaced when something like this happens?
What should I look/listen for when I pick the car up?


I only have ~20,000 miles remaining on my power train warranty so I want to make sure this is fully resolved. I've never worked with rear differentials before so I'm trying to educate myself.

Here's a thread detailing my problems
https://mustangforums.com/forum/2005...rear-axle.html

 

Bearings and races (cones & cups) should be replaced together. If the shavings had affected the gears, the marking compound would have shown the damage. If I had found shavings in mine, I would have redone the whole thing with new bearings and clutch-packs, but I don't know if that's over-reacting...

I can't think of a way the bad pinion bearing could have caused your tire wobble. It's gotta be the axle-shaft, the wheel, or the tire itself. Judging by your video of the hub spinning without the wheel, I'm inclined to rule out the axle-shaft.

If it were me, I would:
Jack up the car until the rear wheels are off the ground. Stack a couple of bricks near the wheel. Lay a ruler or wrench on top of the bricks, with the tip pointing very close to the rim. Spin the wheel (in neutral) and watch the gap. This method is not as precise as a dial indicator run-out test, but with your amount of wobble, it should show you where the problem is coming from.

 

I'm going to jack it up tonight and make sure the wheels aren't wobbling

Here's what Ford did to my car

 

Mmm...that's find and dandy if that was the actual root cause but I would be concerned that the pinion shaft is not centric or that the gears have abnormal wear on them now with extra play you had for a while.

Give it a few hundred miles. If you notice any weird sounds or vibrations, take it back ASAP, a problem still exists and will cause the new bearings to crap out again.

 

Looks like they replaced all of the bearings (both carrier and both pinion) except the outer ones out by the hubs (hard to imagine shavings getting that far anyway). Sometimes bearings are packaged with matching cups (races), which could explain why only one cup is listed among the parts. There is no indication that they touched the clutch packs. As for the pinion gear, they would have found any gear mesh problems via marking compound during reassembly.

 

Didn't get a chance to check out the wheels last night.

Do you think this problem could have been ongoing for quite some time, long before the grinding sound started?

I thought I read something that if my pinion is slipping it could cause Advanced Trac to act up. I have had Advanced Trac freak out on me 3 times now while driving on the highway. Also, my brakes no longer squeak and they had been doing that for months.