I get a clunk under the suspension when I go over bumps or small road abnormalities. I have a 2008 Express Van (15 Passenger). I have 206K miles and it started about 8K miles ago. It does not appear to be impact driving. At high speed, I rarely notice it.

 

Does it bounce a lot? Maybe your shocks are worn out and it is bottoming out causing the sound. It could also be any of the suspension parts that are worn out.

 

No, it does not bounce. It started a couple months after I had the Transmission replaced. It happens more on minor road bumps and it is definitely a "clunking" sound.

 

Possibly a broken transmission or motor mount.

 

upper ball joint.

 

I chased a similar problem on my 1994 G30, but only on the passenger side. It was a "chucking" sound on ripples in the road, especially under light braking.

I inspected almost every part of the front suspension; I couldn't check the lower control arm bushings because I didn't have a way to safely remove the springs. I replaced the lower ball joints and all of the steering linkage. The ball joints were "floppy", the idler arm had what I considered excessive play, the rest of the linkage was OK, but I figured I might as well replace it all (not much more $). The upper control arm bushings were tight and smooth, as were the upper ball joints.

End result? The van steered more precisely, but the noise was still there.

I now have 2 new lower control arm shaft assemblies to be installed shortly. I will report back here with the results.