So here's the story.. I took my wife's 99' ML320 out for a little off roading -- She was a willing participant as were my two kids so I don't feel too guilty. Anyway, we're out climbing hills, going through the mud... having a great time until the car totally quits. The battery died. After some quick investigation -- dodging the intense stares from my wife -- I figured out that the alternator was completely filled with mud. A few bottles of Evian and a quick charge from my buddies Land Cruiser and we were off again. Everything was fine until later that afternoon when I took the ML out of Low Range and started down the highway to head back to home. About a mile out of the off road park the ML came out of gear -- no warning, no lights, no noise, it just dropped out of gear. I proceeded to pullover and stop, put it in neutral and then back into drive which worked great... we drove it home 400 miles without a problem. The cars been running great until last week (3 months later) when it came out of gear again -- same fix... pull over, neutral, drive, zoom...) Well it happened again last night while my wife is down visiting her grandparents (500 miles away from home)...:-{ My wife is really starting to get worried, which worries me because she's hinting she wants a new car and I really don't want a car payment.

Anyway, enough of my drama... Any ideas what could be causing the car to disengage from drive? Other than this problem, the car runs great: it get great gas mileage, doesn't make any weird noises, and it's a real pleasure to drive. After reading the "ML320 Stuck in Death Valley" I beginning to believe it's an electrical issue with the transfer case. My dad seems to think I have a transmission problem.

Here is my plan of attack:
1) Pray that my wife makes it home
2) Check out the transfer case wiring connectors
3) Change the transmission fluid (did not know this was possible until I read this Form -- thanks)

Beyond that does anyone have any other ideas and/or experience with type of problem with an ML? Any helpful advice would be greatly appreciated!

Thanks in advance...