Can you be more specific with the "awful driveline noise"? Does it happen all the time and increase in amplitude/frequency as you speed up? Is it only when going forward under power and quit when coasting? Is it only in certain speed ranges?

Having gone through the notchy U-joint issue myself, it typically manifests itself in certain speed ranges. With the rear end in my car, it was worst from ~55-57mph and came on again around 70mph. It showed up as a vibration and a drone you could feel in your butt, but didn't really make anything else in the car vibrate. It was definitely a strong vibration too.

If the noise/vibration is constant, I'd be looking at the differential or the output shaft bearings on the transmission. Elaborating on what the noise is and when it happens may give clues on what you should be looking at, it may not be what you think it is!

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]