Most OEMs stamp the diff with codes to indicate the internal configuration including the ratio, but I don't know how to decipher Mercedes' codes.
If no one else come through, the easiest way to check the ratio is to jack up the rear and turn the driveshaft for one complete revolution of the rear wheels, and compare your number to available ratios. The early US spec 300E has a 3.07:1 ratio, but I think later years might have a 2.93:1. The early 260E is 3.27:1, and the 300SE is 3.46:1, so these are likely candidates, but there may be other ratios for other markets.
If it's an open diff and both wheels won't turn together, hold one wheel firm, then count driveshaft turns for one wheel revolution, and multiply your number by two.
Last edited by Duke2.6; 05-24-2003 at 11:35 AM.