Rear noise... the crazy clanking is maddening!

[81240D]

I had the some problem with 1981 240D . it was the CV Joint / half shaft
. You probably have to replace it .

[torkq]

I think for now it just needed grease, I haven't heard even a whimper from it since I bathed it in grease, hopefully it'll give me atleast a few more months, while I save up for rebuilt (maybe even new?) axles

[Benzoid123]

Yeah when my half shaft died on my 84 300D it sounded just like that. Mine made no noise until they heated up when on the freeway. It sounded like a jackhammer in the trunk. If you plan to keep the car for a while, just buy a new one (or two since as my dad used to say "Sh*t breaks in pairs") from autohausaz.com. They go for like $300-$330 each but they won't give you anymore problems. I did a lot of freeway trips on that car so I wanted a set that wouldn't let me down in the middle of nowhere.

[RSK_W123_230E]

The sound on your wave file is linked to rotational frequency, a wheel bearing would be a constant grinding and change if you move the steering from left to right, thereby loading the bearing. One of your half-shaft joints has gone which explains the clunking frequency changing with speed.