Strange shudder

[William Hicks]

2004 S320 CDi, 110,000 miles. When moving off from cold, there is a slight but definite shuddering through the car. After a couple of miles it disappears, and the car is as smooth as normal, almost as if something is warming up. It has been happening for some time, and new tyres/balancing has failed to stop it. Garage has checked the transmission, UJ's etc and says all is OK, but it is definitely there. Any ideas?

 

[LostKiwi]

Is it misfiring?

 

[William Hicks]

Is it misfiring?

No, definitely not engine related. I should have said it only occurs between 40 and 50 mph. It feels like a highish frequency shudder from the transmission, but I cannot work out why it goes away after two or three miles. I did wonder if it could be related to the handbrake shoes/drum, because occasionally the handbrake warning light comes on after a cold start - could they be binding until friction heats them up? I am normally pretty good at diagnosing these things, but this one has me baffled.

 

[John Laidlaw]

Might be tyre related I guess, worth checking if the reinforcements have any bulges or....

 

[oigle]

Had something similar with my Fiat Ducato. Was a glow plug relay. Replaced and all OK. No idea if same system applies on Benz.
Ian.

 

[John Laidlaw]

Yip could be the relay- MB Grangemouth were selling those at a good discount recently