Axle/Driveline noise

[Mbz diesel]

I have a 2500 mega cab, diesel, 4X4. There is a grinding type of sounds coming from the rear 30-50 MPH at low rpm’s while lugging the engine. I made a video with my GoPro, dealer doesn’t know what it is. I’m thinking loose pinion nut , bad bearings? Anyone else have this noise?

 

[Mbz diesel]

Here is link to video

 

[dieselscout80]

I would think a pinion bearing or differental bearing would be a constant noise rather than changing with speed changes.

Cool way to capture/document the noise.

 

[jetrinka]

Diff noise could be dependent on speed and load but not engine RPM. That being said it doesn't sound like any diff noise I've ever heard. Most gear noise is a whine that manifests either on or off throttle and most bearing noises manifest in either a growl or a hum noise that usually increases with pitch with speed.

I'd be putting the rear of the truck up on jack stands and carefully having someone run it "in the air" while you look underneath and try and better isolate the area its coming from. I doubt its the diff.

 

[dieselscout80]

I’d get a IR temperature gun and seee if anything is excessively hot too while on the jack stands.