May have just been a cv joint that was fairly dry. On the remainder of the trip not getting hot enough to clunk again perhaps. I would relube the axels at this point or add some lubricant.

I do not see how those balls rolling around in the corkscrew slots in the cans have anything to do with the splines on the axle shaft yoke. there was no prob getting them out on either car i had axles go bad on.

The noise that I heard was like a rod knock or something similar (Heavy, large pieces of metal beating the hell out of each other.) If I could imagine a CV joint self destructing or a diff coming apart, this is what it would sound like. I don't wish to take it on long trips until I can disassemble the rear of the car and the driveshaft. I just don't trust the car. I may also consider swapping a diff for the sake of short term economy and then consider getting the diff assy that is the larger numerical ratio to shorten top speed and aid in mountain climbing. Some grades we will have to climb will be very serious.

More to come and will update with pictures as we start taking it apart.

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83 300TD (need rear wiper assembly dead or alive)
84 300SD Daily driver
85 300TD almost 400k miles and driven daily.
98 E300D *sold
86 300SDL *sold and made flawless 10 hour journey to new home.

I have heard that the splined end of the shaft may not release from the hub assembly making it easier to replace the trailing arm/hub assy at the same time.

I have no personal experience with this, but the concern seems reasonable.

I agree that the CV has zero effect on the shaft ends. I do not believe any comments above suggested that. If I alluded to that, oops, sorry.

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83 300TD (need rear wiper assembly dead or alive)
84 300SD Daily driver
85 300TD almost 400k miles and driven daily.
98 E300D *sold
86 300SDL *sold and made flawless 10 hour journey to new home.

Either add some lubricant to your outer cv joints if the boots are intact and not leaking. Or remove the axels to clean out the old lubricant if any is left and reinstall the axels after relubing on the the opposite sides.

This should give you 100-200k additional miles with a little luck. Continue to drive the car and the the damage will increase until they are no longer fit for a relube or oil addition.

Your initial description was exactly what to expect on a highway trip with inadequate lubrication in a cv joint. Almost any other component in the area of your complaint will not temporarily seem to heal. Once noise generation is started it just will stay and get worse.

Do check the oil level in the rear end if you have not just as a general maintenance thing. It is not the source of intermittent clunking though.

In my opinion there is a ninety percent chance that your issue is just a semi dry cv joint at this time.

Looking for something else is in all likely hood a waste of time. Plus if driving it you will be increasing the damage to the cv joint even if you do not hear it. You want to use 80-90 weight gear oil as the lubricant.

I will just remove both sides, disassemble, clean, and assemble with fresh lube. Gear oil, not CV grease? Any suggestion on good boot replacement? Mine are starting to show cracking in the rubber, but are still dry. If there are going to last another 20 years, I am not sure the boots will.

Exactly why I wish to resolve this issue now.

Agree.

It is thought that low oil could cause intermittent noise as the oil moves around.


I like the sound of that.


Not big on wasting my time, but I also do not see a lack of benefit in replacing bushings, cleaning the diff and relubing, servicing the axles, replacing the brake flex hoses, servicing the drum in hat and removing the driveshaft to make sure it and it's joints are in good condition. There seems to be a tiny but of play between the front and rear sections of the driveshaft. No idea what is acceptable. Good time to check or update the flex joints.

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83 300TD (need rear wiper assembly dead or alive)
84 300SD Daily driver
85 300TD almost 400k miles and driven daily.
98 E300D *sold
86 300SDL *sold and made flawless 10 hour journey to new home.

Check the centre nut on the driveshaft for being fairly tight. By observation you should be able to see if that slop is in the universal joint first.

I did not intend for my earlier remarks being or sounding cynical in any way. In the process of restoring reliability to a 123. I have always felt that dealing with the rear cv joints before the car remained in service was time well spent. Even when there was no current problem. To me the heavy oil is far superior to cv grease. Grease tends to get displaced from the pressure areas.

A few cv joints I have changed on non Mercedes cars seem to still have hard grease in them that has stopped having any help in preventing metal on metal contact in the wear areas. The thinner petroleum liquid component that has bled out of the grease over time and disappeared. Leaving the remainder in a seriously congealed hard condition.

Glad you made it back. I'm sure all of us were a huge help, standing behind you, watching you work while drinking beer.

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1983 240D - For Sale!
1994 Ford Bronco - Awaiting a refresh
2012 Jetta TDI - Wife's MPG machine
2002 BMW M3 - Weekend/track toy
2014 Ford Fiesta ST - DD