Help, Strange Rear Diff Sound

[nklemens]

Just picked up a 200K 1 Owner Rust free '07 burb for a deal. I was not concerned about drivetrain, just rust free. Anyway the rear diff under load is making a strange sound. It is silent slow and coasting. I have never heard anything like it. It's like cats fighting in the diff. Typically over 30 MPH and in 3rd or 4th gear. In 1 or 2 I cannot hear it. We drove it 1000 miles from down south back to new england. Actually sounded like and exhaust rush noise like I had in my 00 burb from the exhaust exiting the tailpipe. I did try the locker and it works fine. I listened with a stethoscope and it appears to be coming from the carrier area but it was hard to tell. I dislike dealers so I want to diagnose and fix myself. Actually sounds like a rusty brake disk in the diff. Fluid is spotless and there was a little film of very fine silver stuff on the magnet. No howling either. I have uploaded a video to google. The site may not allow links, but here it is. https://photos.app.goo.gl/V6xUoKhQsi6Egmks2

[swathdiver]

Sorry, I cannot tell. If you don't have to drive it, I would just tear into it and have a look.

[Wolverine350R]

I can't watch the video right now, but did you make sure it's not the U joint?

[SafetyGuy]

If it were me, I would pull the diff cover and start inspecting!

[Black02Silverado]

Pulling the cover and inspect it. At least change out the fluid and make sure it is filled to the correct level.

[Maxine]

Sounds like someone else's problem a page back and it was their pinion bearings in the rear.

[Supreme Pizza]

Its got to be a bad bearing or something. When I replaced the fluid in my rear end, I filled it up to the "add hole". Rather than putting the plug back in right away, I waited 10 minutes and checked it again. The level was way too low, so I had to add more. I think the thick gear oil takes time to flow into the axle shaft area, so without waiting a bit for the fluid level to equalize - you can get a false "full" reading. This is just a theory, but I think it may contribute to Chevy's premature rear end failure reputation. I agree with these guys. Pull that diff cover and have a look. 

[grizzlyltz]

Ouch !!!

 

 

Grizzly