With engine completely off, turn the key to "on" (don't start engine)(the "on" position is the position where all the warning lights on the dash come on).
Push the trip odometer rest knob twice in rapid succession. The time/distance remaining to the next service will appear in the odometer. OK, hold the trip reset knob DOWN (in), while doing that, turn the key to "off", then back to "ON", keep holding the knob down this whole time, it'll take about 10 seconds, you will here a "beep" from the cluster and the distance in the odometer will change to 10,000 miles.

ps there is a ML/Gwagen/Unimog forum you can post ML questions on.

Gilly