John,

Could be all of the above, drive line, tyres, etc. Porcess of elimination. Start with the drive shaft and center bearing check out. If you recently hit a pot hole, curb, etc,(alloy rims ?) check for bent or warped rims. Jack up one corner of the front at a time and check ball joints, wheel bearing, tie rod ends and don't overlook the possibility of inner bushings on the power steering unit. Somewher along the line you will find the culpert.
Good way to spend a morning or afternoon.

Al, 242 & 245

check the rubber bearing collar on the driveshaft this will cause shutter also if the spring has fell out or it has deteriated from tranny fluid and oil if you have leaks.

You have described a classic symptom of a drive shaft out of balance.

If the vibration is most noticable in the seat, that is often drive shaft.

Also, a fast vibration, faster than the wheels turn, points to a drive shaft.

It might be bearings in one of the drive shaft yokes have frozen, or worn out.

Grab the drive shaft and shake it and/or try to turn it. If it moves at all, something is loose.

If the vibration is in the steering wheel it is often an out of balance wheel. Sometimes you can get an out of balance wheel if something is happening to a tire, like tread separation.

All that being said, vibrations do telegraph themselves all over a vehicle so it could be either wheels or drive line.

Good luck

91-240

i have had balancing weights fall off the rims and I have had my wife ram the dam thing into a curb witht he same effect, an unbalanced tire. Hopefully yours is not a bent rim, just an imbalanced tire.

Did this just start happening? What have you done to your car recently that could have caused this? Tires of driveline could be the problem. You could have one or more unbalanced tires, or maybe the driveshaft is no longer balanced (a weight could have fallen off or it could have been reinstalled incorrectly if you have some related work done recently). Maybe you just had your tires balanced and the shop did it wrong (happens to me frequently)?

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Matt L. -- Cary, NC -- '91 740 wagon