Hello,
I have been reading for a long time this great forum and I am going to post here my case looking for some advise. First let's describe the patient.
It's a 2004 W211 E270CDI (OM646 Engine, not sold in the USA) with 120.000km on it. Everything working great except the automatic tranny. In the winter cold, and only the, when I first star the car in the morning and pull it out of the garage with low throttle, the first or perhaps the first couple of shifting happen with a jerk as if in a manual transmission car the clutch was released too early. If after that jerk/slipping I fully release the throttle I can hear a little noise and the car seems to have more engine braking than desired.
During the rest of the day the transmission works perfectly, and out of the cold winter it works great, too. I assume it's directly related to the oil temperature.
The gearbox has been serviced twice with full flush (last time 20.000km ago) with MB fluid, the electrical plug was changed during each flush although it was not leaking. Oil level is ok measured with engine running, hot oil and in P. It's not affected by the glycol issue. I have a SDS/Xentry terminal, no fault stored. Just in case, engine mounts are not in very good condition, but the car does not show any vibration at idle yet.
I am not any MB specialist, just an aerospace engineer who loves cars even more than aeroplanes. In any case, I have reading the 722.6 common failures -as well as all kind of technical data of the transmission- and mine appears to the related to the Torque Converter lock-up clutch. As the symptons are being showed just once a day and perhaps 20 days a year, I am not going crazy or opening the gearbox. I have in my mind a few steps:
- Check the behaviour in Winter/Comfort setting instead of Sport program.
- With SDS, disable the Torque Converter lock-up clutch and check the behaviour.
- With SDS, read all the adaptation parameters to see the "life" of the transmission.
Unless otherwise evident appears, perform a Torque converter lockup adaptation with SDS.
Should I do/check anything different?
Thanks
I have been reading for a long time this great forum and I am going to post here my case looking for some advise. First let's describe the patient.
It's a 2004 W211 E270CDI (OM646 Engine, not sold in the USA) with 120.000km on it. Everything working great except the automatic tranny. In the winter cold, and only the, when I first star the car in the morning and pull it out of the garage with low throttle, the first or perhaps the first couple of shifting happen with a jerk as if in a manual transmission car the clutch was released too early. If after that jerk/slipping I fully release the throttle I can hear a little noise and the car seems to have more engine braking than desired.
During the rest of the day the transmission works perfectly, and out of the cold winter it works great, too. I assume it's directly related to the oil temperature.
The gearbox has been serviced twice with full flush (last time 20.000km ago) with MB fluid, the electrical plug was changed during each flush although it was not leaking. Oil level is ok measured with engine running, hot oil and in P. It's not affected by the glycol issue. I have a SDS/Xentry terminal, no fault stored. Just in case, engine mounts are not in very good condition, but the car does not show any vibration at idle yet.
I am not any MB specialist, just an aerospace engineer who loves cars even more than aeroplanes. In any case, I have reading the 722.6 common failures -as well as all kind of technical data of the transmission- and mine appears to the related to the Torque Converter lock-up clutch. As the symptons are being showed just once a day and perhaps 20 days a year, I am not going crazy or opening the gearbox. I have in my mind a few steps:
- Check the behaviour in Winter/Comfort setting instead of Sport program.
- With SDS, disable the Torque Converter lock-up clutch and check the behaviour.
- With SDS, read all the adaptation parameters to see the "life" of the transmission.
Unless otherwise evident appears, perform a Torque converter lockup adaptation with SDS.
Should I do/check anything different?
Thanks