RLx02

The other day I put new rear tires on the c55 and now it makes a really weird noise from what sounds like the transmission tunnel. It only makes the noise when I'm a little higher up in the rpms and let off the gas. It sounds like a baseball card stuck in a bicycle wheel, except made of metal.

Here's a video of the noise. Other than the CEL and the noise, the car does not drive any differently. It feels completely normal.


I have a CEL and it said P0730. My guess is that my flex disc has gone bad and the driveshaft isn't aligned correctly?

Thanks guys.

MyMBbaby

I can hear the noise clearly and it really signals that something is wrong with the car. Have it check with a mechanic or the dealer to know the main problem.

alkrstev

Not sure if this will help(C32 TSB) or if this problem would throw a CEL, but here you go:

Body - Scraping Noise From Transmission Tunnel Area

Date: October 8, 2004

Order No.: P-B-88.30/36

Supersedes:

Group: 88
SUBJECT:
Model 202.022/023/024/028/029/033
Model 203.040/061/064/065/076/081/084/261/264/281/284/740/747/764
Model 210.020/025/055/065/070/072/074/082/083/265/282

Scrapping Noise from Transmission Tunnel Area

If you receive customer reports in the above model vehicles of a scraping noise from the area of the transmission tunnel, the insulation above the transmission may have warped and is scraping on the propeller shaft. To resolve, perform the below procedure.
1. Make a bracket to support the transmission tunnel insulation by taking a strip of aluminum approximately 2 mm thick.

2. Cut the strip 40 mm wide and 220 mm long.

3. Drill a 6.5 mm diameter hole in the center (Figure 1).

Warning! Under body components may be hot, use caution.

4. Detach central heat shield above exhaust system and slide toward the rear (Figure 2).

5. Remove nut retaining insulation (Figure 3, arrow).

6. Bend aluminum strip to conform with tunnel contour.

7. Fit aluminum strip on threaded stud and reinstall original nut.

8. Reinstall central heat shield above exhaust system.

Note: The following allowable labor operations should be used when submitting a warranty claim for this repair.

Viper98912

crawl under the car and check the driveshaft tunnel, including the shafts, bearings, blocks, mounts, and ujoints

Supgee

Alkrstev is correct I think, according to the Mercedes WIS.
"grinding noise in transmission tunnel"

cause: sound deading mat deforms at rear tunnel and rubs against the propeller shaft

RLx02

That's what I thought it was. I researched the forum before I asked the question but if that's the answer how come it only happens when I let off the gas?