Originally Posted by cleeves

Symptoms: Gear scraping noise that is 3-4X wheel speed, which does not change when the gears shift. So it's not on the axles or on the wheel bearings or on the engine side of the trans. When you decelerate between 10 and 20 but put the car in neutral it almost goes away, which means it is effected by the engine load. Mechanic does not hear anything on either trans or diff when the car is on the lift. It makes a different timbre of scraping but still nasty and same speed (3-4X wheel) when backing the car up.

So it leaves it to something on the end of the trans or the differential. It "sounds" like its coming from the back of the car, and with the gear type noise that does not change with gear shift I think it is the diff and not the back of the trans. To clarify this does not sound like a bearing noise it sounds like a gear. I had thought it was the diff oil too low. But both the diff oil and trans oil were changed 2 years ago and the mechanic confirmed they looked fine. So it's not the diff or trans oil. Mechanic has been in business doing MB since 1974 -- strikes me as very experienced -- and says he's never seen an issue like this. Perhaps other people would have just waited until the diff failed catastrophically, but I took it in thinking it was oil too low and would be an easy but immediate attention needing fix.

Any other thoughts ?

I will discuss this spacer concern with the shop! Thanks a ton for the info.

-Henry