Rear suspension or axle clunk when getting on or off the gas.

[atikovi]

New to me 2006 6-speed with 180,000 miles. Whenever I even lightly step on the accelerator or take my foot off it, I hear and feel a clunk from the back like some suspension bushing is loose, worn or missing. Even parked in the driveway I can look out the door when letting out the clutch and actually see the axle moving slightly when it clunks.

Right now I have the rear up on jack stands at the frame so the axle is free to hang down. I tried using a pry bar to move things around and hopefully see what's loose, but got nothing obvious. I know these models had a recall for lower control arms, but the recall is not open on this truck so it was probably already done. The upper control arm looks pretty clean but don't know if it was replaced 1 year ago or or 5, or if it's a cheap low quality part.

Two unusual things I noticed. With axle hanging, I can move the coil spring around. And I can lift the axle up by hand almost an inch with no resistance. Is the shock bad? What else to check?

 

[u2slow]

Upper arm bushings. They tear. Best viewed when not jacked up.

It is very difficult to remove the OEM bushings without stretching the holes (then new bushings won't stay in place.) As careful as I was, still had to tack-weld the new Moog ones in. They didn't last long either, so I swapped over to another used arm.

 

[duderz7]

Jack it up by the axle so it's closer to ride height during inspection. The bushings mentioned would be a good place to start, next the ball joint on top of the diff, check for play front to back. Also loose shock hardware or bad bushings there. Lower arms, and I joints at the drive shaft. Any of the could be clunking. I don't suggest trying to replace bushings or ball joints in the original arm either as mentioned before. Axle movement is not necessarily bad, keep in mind it's only rubber holding it in place. Oh and the loose spring at full extension just means you need new springs and shocks because they're worn out.

 

[atikovi]

OK I'll take a closer look tomorrow.