new550

Hi guys - I have a 2007 s550 4matic and upon putting car in reverse and travelling a few feet, say halfway down the driveway, I hear a single, muted "thud" sound...only in reverse and only once....any ideas on this one?

Thanks!

Corsa9000

Is your driveway flat or at a slope? Do you get the same "thump" after engine is warm and on a flat surface?

If the driveway is sloped, I am thinking pre-safe or other safety feature might be activating.

Let us know what you find out please.

skrontz

I think I hear the same thing every time I pull out of the garage; it comes from the left front side. Doesn't bother me much.

azizblue

i swear same problem.i brought it to the dealer and thay sad everything is ok

new550

very small upward slope...not sure if this is different when flat, but I don't think so...I will see if warm vs. cold has any impact and report back...

new550

I spent some time analyzing the thumps...upon reversing (e.g. out of parking space, etc.) when I first apply the brake, the "thump" is toward the rear of the car and happens every time, irrespective of slope etc. Ideas?