I recently had the lower control arm bushings replaced in the C280 because of the popping sound and less steering stability.
But I am still hearing a clunking sound! I am beginning to think that this 'other' clunk might be transmission or driveshaft related.

I hear these popping sounds most often when stepping on the gas (more so when pushing it hard, but sometimes when accelerating moderately) from a standstill, it happens in Reverse and Drive (1st gear). I have also heard it when the trans is dowshifting when I gun it. I think I have also heard it when I'm slowing down (ie, around a corner). But I do not notice any fluctuations in RPM whenever the clunks are heard.

Also, when I hear this clunk when I step on the gas from a standstill, it is also a symptom of my "acceleration resistance" ... only now it sometimes has the added clunk to it.

I did a search and came up with quite a few transmission clunkings, but they were mostly upon deceleration or coming to a stop, while mine seems to be much more symptomatic when accelerating. But I did come up with the possibility of failing flex discs or differential mounts, and maybe even a vacuum leak.

Other than that, transmission operates and shifts just fine, and has also had great maintenance, but it's definitly been worked hard.

What do you think? Thanks for the insight.

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2006 E350 w/ 155k miles (Daily Driver)

Previous:
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)