I drove the E320 about 25 miles. It shifted well - no noise and performed normally. Then I stopped at a stop sign and idled at a stop for about 2 minutes. I accelerated and turned to the left. Even though I was pushing on the gas pedal and the engine rpm was increasing, the transmission seamed to be disengaged. I shifted from D "drive" to 3rd. The car was coasting and still felt like the transmission was not engaged. I rolled into a parking lot and checked the fluid level and it was right on the full mark. There were no leaks. During all this, the transmission did not make a noise - no grinding, no wining, and no shifting. During the tow home, the tow driver mentioned that Mercedes can have vacuum leaks that can affect shifting or maybe a computer stopped functioning leading to no shift.

Car history:
I purchased at 157k. Installed new water pump. New drive shaft center bearing.
158k
Original trans fluid was pink when I changed it. I just changed the trans fluid (drained the torque converter and change the filter) just before this trip. I followed the procedure in the Mercedes service manual and used Dextron III fluid. Any help would be appreciated. Thanks, Paul