What's the symptoms both from a feel and sound perspective of a bad rear axle on a W124 wagon?

More importantly, how do I diagnose a bad rear-axle vs. bad rear diff.

I have a fast "waa-waa" sound that comes on between 45-80mph ONLY during accelleration.

I had the car on jack-stands, and could hear it (not feel it) both with and without wheels on. It sounds like from both the left & right sides. I felt a vibration in the rear-diff, but I don't know if that's normal or not.

FWIW, the rear bearings have been replaced about a year ago.

Would worn rear-diff bushings produce the same symptom (e.g., waa-waa sound on acceleration ONLY, goes away when lifting off the gas)?

TIA,
:-) neil
1988 360TE AMG
1993 500E

Perhaps the driveshaft center support bearing?

Feel any vibration at the center drivetrain hump inside the car?

Another related idea that I read here is a swap of the half-shafts. When you do that you start almost over again on CV joint component wear.

Ken300D

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1982 300D at 351K miles
1984 300SD at 217K miles
1987 300D at 370K miles

Neil, be very careful about this with a limited slip. I think you should take it out and rebuilt it. What I believe is happening is the differential carrier bearings might be going bad which causes the gear teeth to not "hit" in the right spot and they make a whine/humming noise especially when you decellerate. Acceleration I havent heard it as much.

But there are shims on the side of the differential so that everything is aligned. I think that Bergwerks knows how to shim mercedes differentials, since I know you are good friends with Carl, you should talk to him about what I am bringing up, and see what he thinks in light of what I think.

Let us know.

Speaking of limited slips, have you gotten the 3.27 190E limited slip ready for me?