W124 drivetrain vibration/rumble

[2.5Turbo]

What's next?!

My 124 has developed another problem...now something in the drivetrain is vibrating above 40mph. At first I thought out of balance tire, but I noticed the intensity drops dramatically when cruising at part throttle, and increases on acceleration and coasting. The frequency of the vibration coincides with the speed of the car, not with the RPM, so it looks like it's driveshaft/diff related. I'm guessing flex discs are a good place to start looking...sure hope my driveshaft didn't somehow get out of balance.

I'm sort of wondering if it's related to getting stuck in the snow a week and a half ago; it didn't do it before then and today was the first time I had it on the freeway since then. Did a lot of rocking and wheel spinning trying to get the car out.

This does give me the opportunity to use my new mechanic's tools, jack and jackstands I got for xmas...guess my car noticed I finally had my own tools and decided to give me something to use them on