95 E320 Wagon Transmission
 

I stopped at a light, and the car wouldn't shift into first. I was able to shift it into 2nd gear and drive, slowly albeit, till i could park. I was able to drive it home and now it's parked. i think I'll take it to the shop tomorrow.

Also at times, when going up a hill especially, I hear a clunk sometimes when it shifts.

I guess this could be a number of things, but if anybody could provide an indication of what this probably is I would appreciate. The Car has about 120K miles.