Vehicle has 60K miles of mostly suburban highway mix; almost 0 miles off-road.

The noise appears to originate from the left front wheel area. It can be felt in the steering wheel. It is related to sharp up and down transitions and is more pronounced when the front end is unweighted such as when the car is traveling uphill. If the up-down motion is slow or the front end is weighted (car traveling downhill) the noise is less pronounced or not present. Noise does not appear related to position of steering wheel.

In milder transitions, the noise is a low frequency squeak (like metal rubbing metal). When passing over sharper transitions (such as a raised manhole or pothole) the noise is a light metal-to-metal popping sound. If there is a series of transitions, the noise is a steady pocka-pocka sound. When passing over washboard pavement, particularly when going uphill, the noise can be a louder pocka-pocka (metal hitting metal) sound.

The left front tire is showing excess wear on the two inner tread grooves. All of the other tires were wearing evenly. The car has always tracked nearly perfectly straight and has never been aligned to my knowledge.

I asked an independent repair mechanic to investigate the possibility of loose or damaged left front suspension components, warn parts, missing or worn bushings. He says the left inner tie rod is slightly worn and both inners should be replaced. All other suspension components look OK. There is no detectable movement of the left wheel when side force is applied either on the ground or in the air.

Does any suspension expert out there suspect that the noise could have another more probable cause (perhaps one that is undetectable visually)? Any other possibilities that should be checked?

jbors -- Although there was no asymetrical tire wear, I was experiencing a seemingly similar clunk about a year ago on a '99 ML 320. I must admit that my diagnostics were not as thorough as yours (i.e., uphill/downhill differences, etc.). However, once both right hand front stabalizer/sway bushings (at the frame-mounted link and at the lower control arm) were changed, the problem was no longer evident.

Hope this is of some use to you.


Geoff

a lot of times the sway bar links will cause a clunk from the front end. the lower ball joints wamy aalso be the culprit, but i imagine the tech would have noticed those in service. i imagine your dealer would be able to figure it out very easily.