That is a common Fored problem. The vehicle is good for 3 yearsr 36K miles. The problem is the pinion bearing and the pinion race were not matched correctly. I had one replaceed on my E-350 super duty at no cost.

The noise will only get worse but will not come apart for many miles. Let me know

Answered by losone
7 questions asked

How can I tell what rear is in my E350? 9, 10.25, dana??
How difficult is it to change out the pinion bearing?

Response from clw
1 question asked

The tag is on the very top of the housing. The problem is that the ring and pinion are also misaligned by the pinion being being out of tolerance. You need to talk to a Ford person that really knows those rear ends.

If it was me, I would change the pinion bearing and align the ring and pinion. Make sure you buy a new crush washer for the pinion. You may end up with a little noise but nothing like you have. Good luck

Answered by losone
7 questions asked