G20 rear end weirdness

[David Pertuz]

The list lives! I thought I'd dd to it. Excuse the cross-post if you see
this twice.

In the last few days I've noticed a problem that is becoming increasingly
evident in my G20's rear end.

There is a rhythmic whining sound coming from the rear (I am almost certian
it is coming from the rear) of the car that is quiet but not hard to hear
with the radio off. It is accompanied by a vibration. It took me a while to
notice the vibration as a problem, since I have a slightly out-of-balance
front tire, but it is clearly a different vibration, and there is the noise
too. Resonant frequencies seem to occur at about 35 and 70.

Probably not coincidentally, but possibly, I noticed for the first time the
other day that the rear tires are worn abnormally. Both of them are worn
heavily on the inside edge, in a pattern suggestive of toe-in. However,
nothing on that end of the car has been touched in the year and 25,000
miles that I've had it, and if a condition had existed when I bought it it
would have shown up a long time ago. The car's handling does not suggest
weird alignment, but something in the rear end is not right. I did have an
eye-opener last winter when the car started to come around on me at low
speed on an off-ramp, but that was a one-time event, and I'm confident it
started at the front tires, as I could feel the slip angles going up in the
steering a second before it broke loose.

Any issues that any of you know of or have experienced that could tie these
two things together?

Is there anything in particular in the rear suspension I should pay
attention to? I have not yet had time to jack the car up and poke around,
but hopefully I will be able to do that tomorrow.

Oh, and there is also a loud clunk that I hear in the back end when I
reverse and then apply the brakes (as in backing into a parallel parking spot)

Hopefully something will stand out at me tomorrow, but I wanted to put it
out here first.

thanks,
David