clunk in rear delayed reverse to drive
Thread Starter
Junior Member
Joined: Jun 2024
Posts: 50
Likes: 9
w204 c300 3.0 flex
clunk in rear delayed reverse to drive
Car drives great. Finally got almost all the kinks out of it. However. We have an issue when going from reverse to drive or drive to reverse there is a noticeable delay. When accelerating then letting off and back on it's a noticeable clunk feeling but no noise.
Checked the driveshaft it seems solid.
Transmission bushing looks ok but could be perished.
It feels like worn out differential bushings.
Any common faults on this chassis that show up as this clunk?
Transmission shifts like butter on upshifts when loaded
All drivetrain fluids are fresh.
133K
2008 C300
Checked the driveshaft it seems solid.
Transmission bushing looks ok but could be perished.
It feels like worn out differential bushings.
Any common faults on this chassis that show up as this clunk?
Transmission shifts like butter on upshifts when loaded
All drivetrain fluids are fresh.
133K
2008 C300
Last edited by olebenz; Dec 15, 2024 at 04:09 PM.
Thread Starter
Junior Member
Joined: Jun 2024
Posts: 50
Likes: 9
w204 c300 3.0 flex
722.6 adaption?
So just wondering since Ive never had this issue before, just recalled that the drive adaptions were cleared and this was the first drive after. Is there something that needs to be done or it just learns over time. Thinking that might be the issue since everything underneath looked solid despite its age. Also again never had this clunk before. This is all of a sudden. Only drove maybe 5 miles since the adaptation clear.
Well following up on this. It does appear it was clearing the adaptations. Had them cleared again and then drove slowly for about 15 miles.
No more clunking. There is a very slight flare going into fourth only. No other gears do this. Fourth does about a 100-150RPM flare. It hopefully will go away over time. Now when providing a little more throttle it does not flare.
Well following up on this. It does appear it was clearing the adaptations. Had them cleared again and then drove slowly for about 15 miles.
No more clunking. There is a very slight flare going into fourth only. No other gears do this. Fourth does about a 100-150RPM flare. It hopefully will go away over time. Now when providing a little more throttle it does not flare.
Last edited by olebenz; Dec 15, 2024 at 10:14 PM.
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2021 GLB250 FWD, 2023 GLA250 FWD, 2013 C250, 2015 GLK350, 2005 ML350SE, 2003 E320
Wow, back to 722.6 days — envious. Even if you don’t do any of this it will gain most adaptations from just driving around eventually.
IIRC the adaptation process for 5G-Tronic without Star Diagnostics is:
Set transmission mode selector to “S.”
Drive slowly accelerating through all gears not allowing RPM to go above 2400.
Coast to a stop not breaking until transmission downshifts to 1st.
Let engine idle for 10 minutes.
Repeat 3 more times.
Shut off engine, exit car and lock doors.
That resets basic solenoid fill routines and puts conductor plate back in normal adapt mode.
Get back in and check upshifts and downshifts in regular driving modes including “C” for 2nd gear start. Check reverse for smooth engagement. Drive in an area that will allow checking throttle downshifts. 5-4, 4-3, and 5-3 should be sufficient. Stop car, shut off engine, lock doors.
It’s not part of the routine, but I always used to check WOT downshift from about 20-25 mph where I could do it safely.
The 5-4 and 4-3 downshifts should allow the TCU to adapt that 3-4 flare out unless there is an actual problem.
If issues arise, repost and I’ll get out a hydraulic circuit diagram and we’ll see if we can resolve it. All my 722.6s went well past 130k miles and were still flawless when we retired the vehicles.
IIRC the adaptation process for 5G-Tronic without Star Diagnostics is:
Set transmission mode selector to “S.”
Drive slowly accelerating through all gears not allowing RPM to go above 2400.
Coast to a stop not breaking until transmission downshifts to 1st.
Let engine idle for 10 minutes.
Repeat 3 more times.
Shut off engine, exit car and lock doors.
That resets basic solenoid fill routines and puts conductor plate back in normal adapt mode.
Get back in and check upshifts and downshifts in regular driving modes including “C” for 2nd gear start. Check reverse for smooth engagement. Drive in an area that will allow checking throttle downshifts. 5-4, 4-3, and 5-3 should be sufficient. Stop car, shut off engine, lock doors.
It’s not part of the routine, but I always used to check WOT downshift from about 20-25 mph where I could do it safely.
The 5-4 and 4-3 downshifts should allow the TCU to adapt that 3-4 flare out unless there is an actual problem.
If issues arise, repost and I’ll get out a hydraulic circuit diagram and we’ll see if we can resolve it. All my 722.6s went well past 130k miles and were still flawless when we retired the vehicles.
