Its called a B2 piston failure. Its sudden, its unexpected, there are no warning signs, not even a loud bang or wierd shifting or something, it just goes and you can't go forward only reverse. It is embarrasing when it happens on the road. Do a search and check your savings cause its going to cost you between 1k and 2k depending on how far you want to go with the overhaul Sorry.

Any 86-92 Benz owner who hasn't had their tranny overhauled can have this happen to them. It doesn't matter if you use synthetic or change the oil every month, when its time, its time. There is an updated B2 piston design or something make sure they use the updated repair kit.