Hi all bricksters,

I am currently going nuts trying to figure out why I have a vibration at highway speeds in my 1994 Volvo Wagon. I recently got a new driveshaft installed by the dealer as the old one was stuck together (thanks to the dealers half-ass prior replacement of my cars center bearing). Everything seemed ok until I got the car up to 55mph or so and deep droning/vibration took over. I had the tires balanced and two rims straightened. The vibration still haunts me. There is NO shuddering at takeoff just the droning at highway speeds which is SPEED dependant. That is between 50 an 75 mph I get the vibration regardless of gear position or acceleration/deceleration. Rather than write a 4 page essay of the fixes I have tried I will list the details below:

1) Checked motor mounts and they look fine. No sag. Less than 1/4" inch between oil pan and frame.

2) Replaced transmission mount (the original looked fine btw and I probably wasted $50)

3) Checked driveshaft alignment/phase. I marked everything and took it apart to double check the dealers work. I discovered that the two sections only fit together one-way which appears to be correct (yokes align).

4) Output shaft bearing/seal are fine no tranny fluid leaking at all and even checked the seal which looked fine.

5) Center bearing is new and looks fine (came with the new driveshaft). Center bearing carrier is also new.

6) No play at either end of the driveshaft (i.e. no wobbling, signs of leakage or "clunking" when I shake the drive train.

7) All rear bushings look good.

8) As stated earlier I had the tires balanced and two rims straightened which solved a shake in the front end.


Overall, as far as I can recall the vibration started AFTER the dealer installed the new driveshaft. Which leads me to believe that the dealer did something or that the new driveshaft is somehow not balanced properly. I have tried MANY things as listed above and searched the brickboard and sweedishbricks EXTENSIVELY to no avail.

My final guess is that the tires are the culprit or that something in the driveshaft is not right. Any advice, info, suggestions would be GREATLY appreciated as I am about to go insane!

THANKS!