C320 gearbox noise - help!!!

[growla666]

Hi everyone,

Have just bought a 1 owner, 2001, C320 auto with 66k on the clock. 4 hours after taking delivery from the local garage this afternoon I took the car out later on this evening and discovered a strange noise eminating from the gearbox. I can best describe the noise like that when you used to put lolly sticks on your bicycle wheels, except this one is higher in pitch and is definitely speed related. The gearbox changes gear perfectly well and the noise remains when I slip the car into neutral. The noise only occurs when moving. Another interesting point is that the noise reduces when I'm in a right hand bend????:???: I first thought it might be the speedo cable as they are connected to the gearbox in some cars but I'm not sure they are in W202's. Nevertheless the speedo on the car seems just fine. My other thought is that the gearbox is low in fluid but as its dark I'm not able to check and am sure if the level was low it wouldn't change as smoothly as it does. Driving back from the restaurant this evening the noise is definitely getting louder.I'm so worried I might be knackering the gearbox I've driven it back to the garage and have left it on the forecourt. I'm not taking it back until its sorted. Anyone got any ideas what the problem is, how I could resolve it and is the car safe to drive.

 

[type49]

May be propshaft related. Rubber couplings front & rear do wear. Could be something caught or touching propshaft. No speedo cables on these cars.

 

[television]

As Type 49 on this one,cant see it as being a gearbox fault, could the parking pawl be sticky,never heard of one doing that

 

[BLONDIE]

This noise could be the parking brake cable.
Above the exhaust there is a heat shield around the transmission tunnel.
The parking brake cable runs along above this shield, it is clipped to the tunnel. These clips are prone to breaking due to the heat of the exhaust.
If the clips have broken the parking brake cable will rest on the prop-shaft giving a rotational noise.

 

[growla666]

Update - Television any further feedback?

Thanks for the responses so far. A trawl through the posts revealed that another driver had similar probs coming from his gearbox and found the following:

"The techie drove the car and then put it on the ramps. He went straight to the prop shaft. There is a spline drive out of the gearbox that allows a slight variation in the length of the propshaft in normal use. This has a rubber sleeve over it to protect it from road rubbish getting into the slpines. My car was 10 years old and the rubber sleeve had perished such that a 'flap' had made itself so that it functioned exactly as you describe on a 'chopper', it hit the aluminium exhaust cowling protecting the chassis from heat from the exhaust. The nice MB tech didn't charge for his time, so I gave him some beer money."

This sounds feasible so will be sending this link to the garage, who incidentally kindly gave me a courtesy car no questions, which was excellent service - Chesham Car and Van Hire (I recommend them)...does the above diagnosis sound resonable? My car has been on their forecourt for a good 4-6 months and hasn't been used so could the rubber sleeves have perished?

Over you to Mercedesanistas!

Growla