s21701

The 97 C-280 makes this grrrnn grrnnnn grnnnn noise. I thought for the longest time that perhaps it was a wheel bearing in the right front wheel, but a passenger confirmed the noise was coming from the center of the car near where the gear shift is. I've looked through all of these forums and haven't come up with anything.

The frequency of the grinding noise increases with the velocity of the vehicle. When I'm at speed and shift the transmission into neutral, the noise continues the same way until the car loses it's momentum.

Aside from this noise, the car shifts fine, the transmission doesn't leak, and all else seems OK. Could it be the gearing where the speedometer cable goes into the transmission? Or is it something more sinister?

Any help would be appreciated.

stox

Sounds like it could be the flex disk and center bearing for the drive shaft. If it is, run, don't walk to your mechanic. A complete flex disk failure can cause alot of collateral damage.

s21701

That's not the greatest internet diagnosis I've ever received since it sounds expensive. Lucky for me we paid cash for all of our holiday shopping this year so I'm not flat broke!

stox

Diagnosis will be pretty cheap. Just put it up on a lift, and an experienced machanic should be able to tell quickly. Replacing the flex disk(s) is not too expensive. It is the damage it can cause that would be expensive.

s21701

It looks like I avoided a bad one this time. It was some insulation that had sagged that was rubbing along the edges of the front flex disk. The flex disk itself looked to be in great shape. Every now and then I get lucky.

Update: OK, with a knife and some patience, I took out about a hand full of insulation that had sagged onto the flex disk. The noise is now gone. I owe it to Stox for telling me where to look for the problem. Thanks again. This noise has been bothering me for about 6 months.