Reverse Clutch Pack...Mine was doing that too. If you don't get it fixed you will eventually lose Reverse.

A suggestion: Spend the extra cash to have the whole tranny worked through. Dont' dare pay to have it removed and reinstalled with the tech only replacing your reverse packs. You are at the mileage where you likely have wear on other forward drive clutch packs. You probably have some seals ,links and cables that could stand some attention too. Since they are gonna open her up anyway, have them go front to back.

I did that with my 92 400e at about 168K (I was experiencing reverse ticking, slow engagement of drive from reverse and occasional slipping between 3rd and 4th during extreme acceleration)

I got out of my shop for just over 3K ( an independant MBZ only shop) ...that included replacement of all the worn packs, every seal and gasket, cables, etc....The slow engagement to drive was fixed by replacing a pin that was designed too long from the factory. They pulled it and fabricated a shorter pin (forgive me, I don't remember it's proper name).

net, net...she shifts crisp and clean. Good luck

__________________
Jeff
'87 300E
'92 400E
'06 ML350