Transmission 722.6 Shifting Problem
 

2004 MB C240 4MATIC Wagon with 160000 miles
Here are the symptoms:
-from cold, shifts are perfect, smooth, no problem at all
-approximately after 5 minutes of driving, SUDDENLY 2-3 shift becomes hard, car shakes back and forth, jerks
-all the other shifts remain smooth

Work performed:
-scanned engine and transmission computers, no codes (Autel DS808)
-flushed tranny
-replaced filter, conductor plate, electrical connector, fluid
-tested all 3 shift solenoids for resistance, clicking, and pressure holding...
-fluid level is perfect

I don't feel like this condition improved at all, comparing from before service.

It is 4MATIC, so I have replaced fluids in both differentials and transfer case.

I filmed all this, it is on youtube, Dieselmercedes.

Anybody familiar with this and knowing the SOLUTION ?

Will be next to install Sonnax 68942-05K Overlap Control Valve Kit ?

Thanks for sharing.

Petr

Something to know about the .6 , the shift solenoids are energized only during the shift and are off when the shift is complete.

I'd do the sleeve kit. There is a torque converter valve kit and I think one other one that can be installed without reamers.

You need a glycol test of the ATF because those cars are known to leak antifreeze into the transmission cooler circuit. The resultant glycol contamination will give the symptoms you describe. Replacement of the trans and torque converter is the fix. If the glycol test is negative then the shift adaptations need to be erased to see if the symptoms go away. If it does then it is a problem in the trans control module and there is an updated module that addresses this problem.

Sorry to disagree, but the fix is to replace the Valeo radiator, which is a well known problem on the '04 203/209 MB's. This will prevent the contamination issue from re-occurring. Flushing the transmission and cooler lines will take care of the symptoms described by the OP, which is caused by contamination of the torque converter lock-up clutch. It may require a second or even third fluid change, but the transmission will be OK.

Of course this assumes that coolant contamination is what's causing the problem in the first place. A faulty transmission ECU can cause the same symptoms. I've seen both scenarios play out many times............

Thank you for sharing your experience and wisdom.

My C240 was produced 10/2003, is there still possibility of having bad Valeo Radiator and/or Glycol contamination in ATF ?
I read that it was only until 09/2003.

Thank you

Petr