I bought this car several weeks ago, and have solved all of the issues except this one.. There is a pretty significant driveline vibration that starts at 45MPH, worst at 55MPH, and goes away, or becomes less noticeable at higher speeds..

It appears that both flex discs are new, or have very recently been replaced..

How in the world can go about starting to solve this??? Should I just take it to a shop, and say "fix this", which is not really my stlye??

Jay..

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89 300SEL Money Pit

92 Blown Buick Ultra Pimpmobile 220K and adding 1K per week

88 Wagoneer Slightly modified (Not for soccer moms)

04 Kia Sedona with every option... NICE

are you sure it is the driveline?

i would check the following

are the tyre pressures correct according to spec.

have all four wheels balanced at a tyre shop.

I have not had the tires balanced, however I did rotate them, and the vibration did not change.. I believe the frequency of the vibe it to high to be a tire anyway.. It's sort of a low pitched droning noise that I can feel in the armrest console, and seat....

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89 300SEL Money Pit

92 Blown Buick Ultra Pimpmobile 220K and adding 1K per week

88 Wagoneer Slightly modified (Not for soccer moms)

04 Kia Sedona with every option... NICE

Brakes are smooth as glass. I feel nothing in the steering wheel.. I rotated the tires with the theory that if one of the rear tires was the culprit I would feel it in the wheel when I put it on the front, but nothing changed..

Another thing that might be of note.. When I accellerate (sp?) quickly through that range of speeds, I really don't noitice the vibration.. It's really noticeable just when cruising...

I had done a little reading, and my wild guess was the center bearing, or center bearing support??? Do they go bad?????

If it were a motor mount, or tranny mount, I wouldn't think it would be so sensitive to vehicle speed.. Only engine speed, and load..