Squeal when backing up.

[am-radio]

I have an 06 envoy Denali. I now have a squeal when backing up. It is loud and kind of sounds like a rubber squeal if that makes sense. It is not the brakes. It does not stop when the brakes are applied. It doesn't seem to do it when going forward. Always when backing up and seems to go away when you hit 5 to 10 MPH. It is very annoying and I'm stumped as to what it is. I jacked up the rear and took the passenger tire off and rotated the disc. It squeals when turning the disc and driveshaft by hand either forward or reverse (truck in neutral). There is no noise from the rear brakes. Any ideas?

 

[The_Roadie]

Assuming the differential isn't dry, I'd bet you have something broken inside the rear rotor top hat area where the emergency brake drum/shoe is. You need to pull the rotors and look.

 

[am-radio]

I tried checking the diff but the plug was so tight I broke my ratchet. I did the old mechanic trick of using a piece of metal to the caliper and the other end to my ear. I then turned the rotor and there was no noise. It seemed to be by the rear diff or u joints. I'll check the top hats to be sure. I've never done that. Never had a vehicle with rear discs. Do I take the caliper off, then the rotor and then I should see the top hat and e brake stuff? Can I leave the caliper on the rotor and take them off together?

 

[Wooluf1952]

The caliper has to come off first.
The same as the front.

 

[am-radio]

Well, had some time to investigate and the squeal was the rear u joint. It was getting pretty seized up. All quiet now.

 

[Wooluf1952]

Well, had some time to investigate and the squeal was the rear u joint. It was getting pretty seized up. All quiet now.

Did you replace it with a grease-able u-joint?

 

[am-radio]

All I could get was non greaseable.