1990 200tqw-Undiagnosed vibration

["Ron Frazier" <frazierx@concentric.net>]

The vibration that I get comes only after I have driven the car for about 70
miles on the Interstate.  For example, I went down to Chapel Hill on
Saturday.  I drove down on the interstate, exited and came to a stop on the
ramp.  When I took of from the light there was a vibration in the back half
of the car as i went through 2nd gear. It was like driving on a wash board.
On the way, home the ride was smooth until I slowed down for the first time
at a stop light.  the vibration was a little more pronounced this time.  But
when I took of from the light and went to my house I did not feel any
vibration.  This vibration does not occur around town no matter how much
driving I do.  It seems that I have to drive on the interstate for an hour
or more.  I first thought that this amount of driving was required to heat
up the tires and the tread was separating or someother strange phemonena.
It does occur under power as well as I can remember.  Today I put the car up
on stands and looked around.  The only thing that i saw that I can may be
suggest as a cause is the appaerance of the drive shaft center bearing at
the u-joint.  The rubber around the bearing seems to have gotten tired and
the drive shaft is not being held in the center.  The rubber is compressed
at the bottom.  I have seen this in my wife's Mercedes and there was a
vibration however it felt sort of different.  But replacing it solved the
problem.  I was distressed to read in the Bentley that you had to replace
the entire drive shaft if you had a problem.  All suggestions and help
welcome.

Ron Frazier
1990 200tqw
1993 100csqw