1992 300E automatic problem? Veddy weird.
 

A friend of mine has a strange problem with his 1992 300E. The car drives perfectly, shinfting perfectly, running perfectly, etc.

When sitting idling, the car is quiet and smooth. When in gear, it still idles perfectly, but makes a "squeek squeek" noise that varies with engine speed, but goes away in neutral. I though of a blet right away, so we swapped a new one in and changed the belt tensioner as well as it looked original.

Same problem. While driving, you can hear the noise, and it goes away when coasting, and then comes back when the driveline is loaded.

The tranny fluid is a little dirty, but nothing to get excited about (not new, but not burnt either...).

This has both of us stumped!

Help!

I'm willing to bet it's a bad motor mount.

I hadn't thought of that at all. It sounds like all the world like a slipping belt, but is only when in gear. Interesting idea, and not too tough to check...

Thanks!