Fix the thing by yourself. Get the shop manual. Mercedes typically don't require special tools to fix. The majority of repairs can be done with ordinary tools. The axles are a do it yourself job. It could be something else clunking like a flex disk on the driveshaft. Don't condemn the axles right away. Shake the living daylights out of the rear suspension and see if you find something else.
Also post the model and year of the car. Why not add it to your signature. Someone here will surely have the same problem and let you know how the solved theirs.
You got a lot of backup here.

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1990 190E 2.6
1996 Grand Voyager 3.3
1985 Mustang GT 5.0 5 SPD
1982 Suzuki GS 750T