1994 - 740i Transmission problems

I have a 1994 740i with some transmission problems. About 3 weeks ago, when the car is placed in reverse, it starts to go backwards and then the transmission slips for a second or two and goes back into gear. This was been pretty consistent. Also, the other day I started the car in the morning and placed it in Drive and the car was having a hard time moving forward. The engine rpm was higher with the car moving very little. Then I placed the shifter in Neutral and the car wanted to go backward. The other odd thing is if the transmission is placed in snow mode using the switch next to the shifter, the car drives fine. It's almost as if the the normal and snow modes are backwards. I've owned the car for two years and it's the first time this has happened. Has any one else experieced this problem or have any suggestions? Thanks, Al