Squeak from the rear of the vehicle

[BigIan279]

I've had my Short Wheel Base Yukon Denali from new since 2016 and it's been pretty trouble-free during that time. But over the past few months, there has been a persistent low speed (up to about 30mph) squeak coming from the rear of the vehicle which has been getting progressively worse and worse. It's sounded like a rubber on metal squeak, so I thought the spare had gotten loose so I dropped it down cleaned it up put some padding between it and the car, but still no good. I can't get the car up on a lift to get a really good look at it, but have given the exhaust a good tugging to see if the rubber mounts were squeaking - no. I've gone through the inside trim and second and third rows of seats to make sure they are not rubbing but no use. Does anyone have experience with this squeaking and know how to fix it? Any tips tricks and fixes would be greatly appreciated. TIA

 

[B-train]

Check your u-joints on the rear driveshaft. They will have a rubber/metallic squeak at slow speeds when bad. Rust around the caps dust boot is a dead give away as well. I've already replaced the rear one in my 2017 about 40k ago. Easy repair.

Take the steps loose at the diffential, then use a prybar to gently remove it from the saddles. You should be able to move it in both directions by hand easily. If you spin the bearing caps and feel binding or roughness, replace it.

 

[BigIan279]

Check your u-joints on the rear driveshaft. They will have a rubber/metallic squeak at slow speeds when bad. Rust around the caps dust boot is a dead give away as well. I've already replaced the rear one in my 2017 about 40k ago. Easy repair.

Take the steps loose at the diffential, then use a prybar to gently remove it from the saddles. You should be able to move it in both directions by hand easily. If you spin the bearing caps and feel binding or roughness, replace it.

Thanks B-Train. The sound is an irregular noise and seems to be more noticeable when "cruising" at 20 to 30mph along a straight "smooth" road and is more like a "jiggle" rubber on metal sound- that's why I thought it was the spare tire rubbing on the underside of the trunk floor or an exhaust hanger. I live in a residential area where there are many speed bumps and the impact and undercarriage movement of traversing those does not make the squeak any worse - so there is lots of squeaking from very little chassis movement. It's a mystery to me. I'm thinking of getting a couple of cans of WD40 and spraying every connection I can see lying on my back on my drive.

 

[houstontaylor]

There are lots of rubber mounts underneath, including body mounts, steering system joints, loose sheetmetal bolts underneath, brakes/bearings. I finally got my 2003 Tahoe quiet after all of the above and more. I wish there were a tool to spacially locate the source of noises.