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

Welcome aboard.

What brand of transmission fluid did you use? I did a transmission service on an early 90's model one time using the cheapest transmission fluid I could find and the transmission did not work at all. Put a premium grade Mercon/Dexron III in it and it never missed a beat from then on. Did you put any kind of transmission additive in it? I've seen a transmission service done with some Trans-x added and the transmission went out shortly thereafter.

Don't believe the bs about the "computer" stopped funtioning. There is none controlling this transmission. The vacuum leak can cause shift quality issues though.

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Jim

Jim,
Thanks for the post.
I am using my favorite trans fluid - Mystic Oil - goofy name but great engine oil and trans fluid. I have used it 1994 e420, 1992 300e 4matic, 1991 300e and other none Mercedes with good luck.

I am hoping my faith in their continued quality is not misplaced.

I would like your opinion:
I read in the Mercedes Owner's bible 1986 - 1995 that if a B2 valve goes out in the trans you lose all forward gears. Are you familiar with this failure? Do think that this would make sense?

There should be no "faith" in the transmission of a 90s mercedes. Either the seals are holding, or they aren't. Pressure controls everything. The metal will all be perfect and the clutch discs will be worn completely down by incorrect pressure caused by a leaking seal. All the metal will survive for the rebuild.

Rubber orings can go out. the pistons can get stuck. The Design is good, its the plastic and rubber that gives you the headaches.

Also suddenly not having any forward motion sounds more like a piston in the valve body not actuating. Vacuum could potentially cause this. Test the modulator, then pull the valve body and clean it if the modulator is good.

Also 2 minutes at a stop sign? my imagination is beginning to go crazy.

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77' 300D, "Cartman" SOLD @ 150K (didn't know what I had)
83' 300SD, "The Superdon" 325k+ @ 28mpg
95 E320 wagon, "Millennium Falcon" 231k+ @ 24 Mpg
95 E300D, "Sherley" 308k @ 33.69 Mpg, currently anticipating a head
99 Suzuki Intruder "Trudy" @ 45 mpg

Today, outside temperature was 48 F, I started the car and tried out reverse. It worked. I tried out drive (under 5mph) and it worked.

Any ideas? Very wild....