Rear axle clunk, both wheels clunk in and out

[Toddster]

Hello,

05 Envoy Denali G80locker SWB w/139.XXX 4X4

Like the title says the rear axle has a clunk on both sides when driving under certain road conditions. Mainly over bumps and dips in the road.
I did jack up the rear end and noticed that both wheels clunk in and out of the axle, somewhere I don't know.

Does this sound like bad wheel bearings or is this something deeper? There's no growling or other noises other than the clunks over bumps and dips in the road and going around corners, depending on the smoothness of the road. The rear axle fluid is 3 years old.

I did just install Markmc wheel spacers last weekend. Yesterday I took the wheels off and retorqued the nuts to 100 lbs per Marks suggestion after 500 miles.

Hope I offered enough information. Thanks for your help in advance!

Todd

 

[CaptainKD]

Welcome

 

[Toddster]

Thanks

 

[The_Roadie]

Axle in/out play is entirely normal; up to a certain amount, because of the design. The axle end inside the differential has a groove machined into it, and c-clips retain the axles so they don't try to depart the vehicle. The brake calipers and rotors won't let that happen, even if the c-clip breaks or comes off, but it's the nature of the design to have 3/16"-1/4" play. Was yours more than this?

Up/down clunking is MUCH more likely to be the poor GM design of the anti-sway bar end links. They go bad often and have been discussed here and on trailvoy hundreds of times. Check your links and also the bushings that mount the anti-sway bar to the frame. The rear shock mounting bolts also can get loose or the bushings deteriorate and then THEY clunk. Finally and less likely, the four fore/aft control arms and the side-to-side panhard bar also have mounting bolts and bushings that can deteriorate. Lots of stuff to check down there.

 

[Toddster]

Ok thanks for the areas to check, But.... I have the front end ruled out because between the last two weekends I've replaced the front upper ball joints, front swaybar end links and bushings, and front wheel bearings.

 

[The_Roadie]

None of the components I mentioned are exclusively front end parts. The rear also has control arms, they're just tubular and don't look like the letter A. The rear also has an anti-sway bar. Panhard bars are only a rear suspension item.

 

[Toddster]

Oh okay thanks I wasn't understanding... I need to do more digging into it.
Thanks

 

[Toddster]

Axle in/out play is entirely normal; up to a certain amount, because of the design. The axle end inside the differential has a groove machined into it, and c-clips retain the axles so they don't try to depart the vehicle. The brake calipers and rotors won't let that happen, even if the c-clip breaks or comes off, but it's the nature of the design to have 3/16"-1/4" play. Was yours more than this?

I took the right rear wheel off and took a look. I swear the noise is inside the axle somehow. Grabing the brake rotor I can move the whole assembly in and out of the axle about an 1/8 inch. You can see the brake caliper move apart from itself. Meaning the two part caliper assembly moves in and out. That Make any sense?

 

[The_Roadie]

There are the emergency brake shoes inside a miniature drum in the middle of the rear rotors. Have you ever pulled them off for inspection or adjustment? Does your ebrake work well?

Calipers move on slide pins to accommodate work pads. Have you changed your brake pads before?

1/8" doesn't seem worrisome.

 

[Toddster]

Funny you should mention rear emergency brake. I actually do use it often. And did inspect it when I did the rear brakes 2 years ago. In fact the only way the movement can be stopped is by engaging the emergency brake.
Thanks for your wealth of information and help. I guess I will leave it be as it sounds like this isn't worrisome as you stated.
Thanks again! - Todd

Btw I'm very glad I found this sight. I had no idea up until a few days ago about the downfall of the OS.