hrmjay

Hi All,

Hope I'm not rehashing info thats already been covered, but I read as many threads as I could on the 722.6 transmission but couldn't find anything that fits the bill.

The symptoms are as many have mentioned where there is a jerk when moving off from a standstill, sometimes a bit violent, thereafter the upshifts and downshifts are smooth as silk. If I'm stuck in traffic I have to feather the throttle to keep from jerking forward, then there is what can only be described as a rocking motion and an accompanying grinding noise.

The really strange thing is that this problem comes up only during wet weather. I noticed this 3 times now, drive in the rain or wet road and over the next couple of days the symptoms show up. Then gradually reduces when dry over a day or so and resumes perfect operation.

Up to now have done the following at a local Indie (BTW I'm in Sri Lanka):
1. Renewed ATF and filter
2. Removed serviced and tested shift solenoids and conductor plate
3. Checked the connector for oil residue - perfectly dry

Would appreciate any suggestions on what to check especially considering the wet weather angle. Could there be anything under there that could be affected by water or spray?

Thanks in advance

Roshan
W211 E240 5 speed

ot1

Have you checked the fluid level yourself? Dipstick part number for a 722.6 transmission A140589152100
Having grinding noise is scary. And there was no metal in the trans pan?

Have you checked all your caliper pads? Front and back, INNER and OUTER pads on every wheel? Maybe there is NO pad and just backing plate contacting the rotor on one of them.
And you need to pull rear rotors to check the E-brake shoes.

hrmjay

The fluid level was checked in my presence......ran the car till operating temp, ran through each of the gear positions, then inserted dipstick and level was as it should be.
Will check the brake pads as described.

The grinding sound only comes when the transmission symptoms come up, not otherwise. And the transmission issue only comes up when the car is run in wet weather. For example Monday was wet here and I ran the car for about 20 miles, parked for about 1 hour, on the return trip the transmission was jerky. Tuesday car didn't run and was sunny, Wednesday sunny, currently car is out with the wife.......no issue, shifting normally, no sudden jerks. Almost as if something got wet and has had the time to dry out.

ot1

Ok, grinding sound indicates metal on metal…and you saw no metal flakes in the pan correct? why I was thinking maybe the brakes…but now maybe the ABS is engaging one wheel because of a bad sensor causing the jerking. Have the codes been pulled by actual Mercedes software on a C4 or such not some crappy scanner ? Are any IC warning lights popping up when this jerking occurs? If an animal chewed the TCM wiring and exposed copper maybe a solenoid is fluttering but this should throw a code and it would be a buzzing sound and not a grinding sound.
People can confuse ABS chatter with grinding. Does your car have SBC braking?

hrmjay

Pan was clean when removed, and cleaned again when refitted.
Will check on the software used, Indy is an ex dealer, with close contact to them still.
No warning lights at all when the issue comes up.
Am putting the car in for a week, will get them to check the wiring and the brakes. The car does have SBC.

BlackML550

As it only occurs when wet, it implies that what you may have is a traction issue via something the ABS sensors that then play havoc with the trans. Look for a slip somewhere. Speed sensors, tail shafts, differential, transfer case if you have one. Any codes like this at all? Not OBD2 codes but MB specific ones.