Unfortunately it was not to be, or should I say, B2. - PeachParts Mercedes-Benz Forum

pwogaman · #1 04-22-2014, 10:10 PM

My 300D 2.5 Turbo, which my son uses at school, had been towed to the University of Michigan student parking lot in January after the automatic transmission forward gears failed in the slushy salted snow. I had a theory about what the problem could be based on some research: the B2 piston for those who want the technical on it. The B2 piston is accessible from outside the transmission and can be changed out without removing the transmission. To access it you need only lower the transmission part of the way while it is still connected to the engine.

Due to the salt, essentially every fastner (nuts and bolts and clips and such) was frozen. Even the rear parking brakes were rusted shut. It took me about 3 hours Saturday evening to disassemble and free up the rear brakes so I could rotate the drive shaft and do what I needed to do to lower the transmission and check the easy fix B2 piston.

The problem was not the easy to fix B2 piston. Time for plan B.

Beginning Sunday morning (Happy Easter), at 10:00, in the student parking lot at the University of Michigan, working straight through, I spent the next 19 hours replacing the transmission. Mind you, I had only once previously taken a transmission out from under a car - that was to get the spare I brought with me, obtained from a pick-and-pull. I've separated engines from transmissions a couple of other times outside of cars too, but I'd never put them back together in either case. There was a bit of a learning curve to the process.

Nearly every fastner put up a fight - frozen with a salted coating since January. My son helped when he could, but he needed to study for exams and get some sleep for an exam Monday morning. When it got dark, I had to use a flashlight. When the batteries on the two of those had died at about 2:30 in the morning, I turned my car towards my son's and aimed the headlights to flood under the car and then used a side view mirror I pulled to reflect light upwards into area in which I was working.

I got the replacement transmission in, which was easier now that the fastners had all been loosened up, and luckily enough it worked! I spent about the next 45 minutes cleaning up my mess and locking up my tools so I could take the car out for a test drive. It was nice watching the sun come up and hearing the morning bird calls. Everything was going great. I took the car out for a spin and topped off the tank for my son, and then brought it back to the parking lot.

And then it got bad, again.

His windows went down, but not back up! My first thought is sticky center console windows switches, as in someone spilled soda on them or something like that. So before I take the door panels off to check the windows for mechanical problems, I checked the switches for electrical problems. It struck me as odd that more than one window was misbehaving at the same time for the same reason. Also, when I pushed the window down switch, then went all the way down automatically. That is a function of the convenience module. Then it struck me. The convenience module will open all then windows when you put the key in the driver's door and hold it in the unlocked position for more than a couple of seconds. It is a quick way to cool off the car when it has been parked in the sun on a hot day. The convenience module will also close all the windows if you use the lock the car from the driver's door. I tried it. It worked! The convenience module was badly misbehaving.

So at 7:30 Monday morning, I gave my son his key, explained the way to close the windows until I got another convenience module, and drove straight home - smack into D.C. evening rush hour traffic. Thank goodness for Harry Potter books on CD.

So that's what I did this past weekend.