I had the exact problem that ILUVMILS just described. The code I was getting from the OBDII scanner was P0715 which points to the speed senson built into the valve body electical plate. This is a dealer item. You have to open the trans fluid pan to get to it. The valve body has to come out before you can replace the electrical plate. Once mine was removes, I could notice some cracks on the speed sensors. I have since replaced mine, but I broke a yellow looking plastic...right by the shift adjuster (not if right name). I actually reassmebled the whole thing before I notice that the car would not move. So I took it apart again, and that was when I noticed that this yellow plastic controlls the pressure within the valve body. I am now looking for that yellow part, so I will not have to purchase the whole valve body....that will suck. I will keep you posted on my results.

Check out this link:

http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=210265&M=112%2E941&GA=722%2E607&CT=GA&cat=23V&SID=27&SGR=100&SGN=10