Help with a diagnosis

[Alberto_Fontova@xxxxxxxxxxxxx (Alberto Fontova)]

My Spider has started to make new noises which are of concern.

I first noticed the noise on the interstate.  It occurs around 70 mph &
the noise itself is reminds of the sound knobby, offroad tires (on a
mountain bike or motorcycle for example) make when they are at speed on
pavement - a sort of humming sound.  When this occurs there is also a
noticable vibration.  It seem to becoming from the rear, right side of my
Alfa.

At 40 mph, on a neutral or trailing throttle, a very distinct and
noticable vibration envelopes the car.   The origin of the vibration seems
to be the rear end and there is a noticable noise although it is different
from the noise that occurs at 70 mph.  This vibration occurs only at this
speed, and in second, third, or fourth gears.

Any ideas or suggestions would be greatly welcomed!

The car is a 1987 Graduate with 137,000 miles on the clock.

Thanks,
Alberto

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