Very Noisy Rear Diff

[rae1961]

This is in my Avalanche but I know it has the same diff as my Tahoe and the Avalanche section does not get as many views.

The noise gets worse on deceleration and more noticeable from Drivers side inside and outside the cab. Noise will go away for a second or two when turning right or when the suspension travels upward. Noise starts around 20 MPH.

I don't think it's the u-joint as there is no play, Pinion bear, axle bearing... thoughts?

Thanks!

Link to video here

[maxwedge]

Welcome to AF. No way to accurately diagnose differential noises wifhout a proper road test or disassembly, sounds like a possible axle bearing.

[rae1961]

Thanks, crazy I joined in 2008 but this is my first post.

I am going to pull the cover and have a look for any signs of damage or metal shards. I took it for a good drive and then checked all areas of the diff and u-joints with an infrared temperature gun looking for a hot spot around the bearings, but nothing stood out.

You mentioned a proper road test, what that entail, or are you referring to a shop doing it?

Thanks!

[71bronco]

Just a quick update in case someone else comes across a similar noise. It turned out to be a bad pinion bearing. Once the drive shaft was disconnected you could feel the play. Nice to drive without the all that noise.

Thanks again.