I have a '99 CRV 4WD 5spd, w/ 42k miles. I recently put 2 new tires
on the rear, the fronts have ~50% life left. Now anytime I lift off
the gas with the clutch out (engine braking) I get a bad vibration
coming from the rear. This occurs in all gears at all speeds, as
soon as I lift off the gas w/ the car in gear, I get the vibration.
It is most noticeable in 3rd coasting down from 35-25mph. Push the
clutch in and the vibration goes away.

The tires have been spin balanced, and properly inflated, and there
is no vibration at highway speeds (as long as you're on the gas). I
changed the rear differential fluid and also the manual tranny
fluid. Vibration still there.

Any thoughts?
Thanks!
Steve

It seems to be clutch related. Perhaps either your
fluid level is down or your throwout bearing is going?