I think you've probably found the culprit - the axle is probably knocking. It is difficult to say how stiff an axle shaft should feel; the best thing to do is to remove the axle from the vehicle and check the torsional wear at several points along its "in and out" position. There are a few videos of this procedure on youtube such as this one =>

How to Test a Mercedes Rear Axle for Excessive Wear - Kent Bergsma - YouTube

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Stretch, thanks for the tentative confirmation, and the link to the video, which originally led me to suspect that the axle was bad. However, I was trying to avoid having to remove it until I had a replacement, and I didn't want to get a replacement until I could confirm it was the axle.

Ergo, even though the video said it had to be removed to test it, I was wondering if I could tell it was bad without removing it. And you just did that to some extent.

Accordingly, I guess I need to look around for a good used axle or a rebuilt one, since the new ones I see advertised seem to be Chinese junk.

It is harder to check the axles on the vehicle - if you raise the vehicle and then lift or lower the trailing arm into different positions you can get the axle to be in different "in out" positions and then you can wiggle / twist the ends to see if there is excessive wear: BUT! Because the axle cans are constrained it is possible to miss the greatest wear spot. It is much easier to find a problem with the axles removed.

As for replacement axles - well vstech (DD moderator) sells rebooted second hand units. Most people report good things about GKN axles. If, however, you get the annular axle type make sure you fit the bolts with loctite. (There have been reports of these bolts coming loose - this is the inboard differential end)

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

swap sides. they're the same and running in a different direction puts the joints on new surfaces. and if the clunk moves to the left, you were right. btw, had an sl years ago with a clunk on reverse then forward. the rotor on the rt rr wasn't bolted to the hub and you could see the hub move, making the noise and the rotor clamped by the caliper. the wheel doesn't trap the rotor as well as i thought. good luck, chuck.

I ended up taking the car over to a indy who specializes in German cars, and he confirmed that it was the axle as soon as he heard the clunk. Plus, it appears that the other axle is also starting to clunk. So I don't think swapping them would be the way to go.

I thought of that, but it doesn't appear to be the case here.

Thanks, Chuck