Anyone have this occurring / know of a fix other than drive faster?

Got car at 161,000, now has 162,000 miles, pulled pan for regular maint, no material just some evidence of graphite in oil, changed filter, old oil put back in.

Feels like torque converter is locking up too soon in 5th gear / holding 5th too long, vibration is like a standard shift that is in top gear too soon. Not an engine missfire issue though I might accept it might be an injector balance issue. ( Engine is electric motor smooth otherwise even with sagging motor mounts. ) One drive shaft joint had been replaced sometime in the past, other is OK but rubber might be getting hard.

Changed motor mounts as they were sagging, this got rid of the harshness of vibration but it is still there. My 97 SL320 with the same drive line does not have this vibration.

Found a reference to this problem on a Chrysler Crossfire message board, it states that a TC relearn might need to be done. Car gets driven from cold 30 to 40 MPH until coolant temp has risen 10*C, stop car wait 20 sec, drive again until temp goes up another 10* C. Once coolant temp has leveled off, drive car 30 - 40 MPH for 10 min at constant load.

Autostick Transmission vibration at low speeds - Page 2 - CrossfireForum.org

( Mercedes TSB )
DTB
Date:
March 23, 2006
Order No.:
P-B-27.60/43b
Supersedes:
P-B-27.60/43a dated May 3, 2005

Any ideas?
Thanks

My 2000 C280 does something similar, although I would describe it as more of a rumble that I can hear vs. a vibration I can feel. The other difference is that it rumbles when the lock up clutch starts to engage, then the TCU disengages the clutch. Also, it only does it in cold temps. It isn't noticeable in warm weather. I had M-B look into it when the car was in warranty at about 100K (it was a CPO car). They changed out the valve body and it helped for a while but it came back around 20K later. Hope this is of some help.

The rumble is partly because of the wrong ATF too, If you had a shop dunk in plain dex 3 and an add pack to make it an HFM fluid then its a hit n miss, the torque converter lockup on these transmissions are very different from regular off the mill units made by others,

MB modulate the converter clutch by controlling in and out pressure - and use no return springs in it. Hence the ATF requirement gets top priority to tick the checklist.

__________________
2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

Well, in my case, the transmission has never been filled with anything but the correct M-B fluid. No "dunking" ever occurs with my machinery.

thats great, you can try the retest procedure and see if it works, I have sort of given up on it - and I have read on other european forums that most people faced droning in the 722.6 boxes if the new 3134 ATF was used which was remedied by going back to the original fill ATF 3403 - which is not available in the USA anymore.

__________________
2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

Mine rumbled with the original fluid. The last time I changed the fluid (during rear main seal replacement) I flushed the entire trans cooling system and refilled with the 3404 from a stock I had accumulated. I gave up trying to fix the rumbling long ago. If I hear the rumble I just select a lower gear until the transmission is fully warmed up.

I also just ignore the 40 mph lockup rumble with cold transmission, Once warmed up all is good.

A person who I know repairs these transmissions (works at a dodge dealer) and has been in a number of oddball problems with these in dodge chargers etc says that fresh Chrysler ATF+4 eliminates this problem. There is a difference in driving though, chrysler atf-4 makes it act like a CVT at light throttle and a hardcore street car at high throttle. He also told me that the dipstick tube O ring can allow some moisture in if its old (dodges drip their ac right on it) - even a little water in the ATF will cause the converter to drone - and the service bulletin dodge gave was replacement of the O ring and a dollop of silicone to seal it and a full flush of the ATF with about 16 qts of ATF in 4 drive cycles.

I never did that, but the guy does that about once a week.

odd bit - the clutch materials in the dodge/jeep/chrysler units when opened for the first time usually have mercedes parts in them but their simpson gear sets have different teeth compared to mercedes.

__________________
2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

It's good to hear ( sort of ) that others are having the same problem. The feel is torsional vibe not clutch chatter. In the old days ( mid 70's ) when Chrysler first came out with lock up TC there was much talk of the vibration being TC clutch slippage. It was really torsional vibe from the TC locking up too soon and then engine lugging.

If the TC would not lockup / trans would not hit 5 th at 40 MPH , 1,200 to 1,500 RPM the vibe would be gone. I "think" the TC clutch is modulated so maybe it it is suffering from clutch drag, it could be applying more than requested.

I need to put a duty cycle meter on the TC solenoid and have a look, will probably add a TC bypass as well to test. When slowing and the trans automatically down shifts from 3 to 2 to 1, there is enough of a bump that makes me think the TC is still engaged / dragging. ( feels like a standard shift without any TC cushioning. ) Car does not cold stall, feel like it is tugging at a stop.

I drive it as is but this is to be Moms car and 40 MPH light throttle is right in the around town range. It may come to having her drive it in 4th.

Oh, as for moisture, I can see that happening. To clean out, some industrial hydraulic systems can have a desiccant filter that will remove moisture, it might be worth a shot.

Hey SL,

Nothing you can do about moisture as the transmission has three ports-one behind the bell on top, and two behind the transmission torque converter, yet you can do fluid exchanges to rid of any contaminated fluid when you do a transmission service. As oil pan drain will get you 40% of the fluid, with a torque converter you will get 75%, yet fluid exchange will get nearly 100%..I do it from the exit port of the transmission, and the exit port is on the drivers side of the transmission for the 722.6..This is how I do it on a W210, and W140..

W210:

Will Vin# reveal Torque Converter Drain Plug - Mercedes-Benz Forum


W140:

What is my transmission? Fluid? - Mercedes-Benz Forum

AND....It is a complete fallacy on fluid shock...I revived many transmissions that were to far gone with a fluid exchange...

Now short of replacing the torque converter their are a few things you can do.. Remember, the 722.6 weakest link is the torque converter, and the valves in the valve that control it, so in a New York second if you are over 100k or so miles and need to separate the engine and transmission install a fully-updated torque converter made by Consolidated Vehicle Converters(CVC) sold by WhatEverItTakes parts

Torque Converters Distributors Page - Consolidated Vehicle Converters, Remanufacturing Torque Converters for Automatic Transmissions

They have all the Sonnax updates for those cold weather issues you guys in the east experience, and CVC 722.6 converters go for about $200 bucks.. Never install a used 722.6 converter on any 722.6-not worth the pain..

Now, back to the fixes you can do short of replacing the torque converter is replace all the o-rings on the solenoids with a aftermarket $80 722.6 seal kit from R/O//C/K--A/U//T/O as Mercedes does not sell the solenoid seals by them selves.. Also, the lock-up solenoid is the one with the most stress as the seal is always brittle hard, so my guess would be even to replace that solenoid too, but to help these solenoids from heat. I would get the plastic shields for the 722.6 that the later 722.6's come with. The shields will on fit onto the revised conductor plate-The revised conductor plate has the copper speed sensor connections covered in plastic where the old one has the copper exposed.

The 722.6 valve body is soft and wears out quickly compared to other valve body's. I would replace the overlap piston1-2gear/4-5th gear with a sonnax unit, but I would replace all of them, and that will radically improve the shifts on all gears for the price of 70 bucks. Since we are taking torque converter, I would replace TCC lockup valve with a sonnax unit. See the attachment.. this may help too..

https://s3.amazonaws.com/sonnax-dev/uploads/unit/valve_body_layout/314/VBL-Mercedes-722-6.pdf

Hope it helps, and I would change all those valves related with shift, pressure and torque converter controls with a Sonnax units. Also the seals...

All the best,


Martin

Attached Files

722_6_VacTestLocations.pdf (543.3 KB, 244 views)

I have felt that in nearly every car with 722.6 that I have driven. I do get the tug tug tug jerking when dead cold but none when hot, picking some brains of some members and reading their posts about such - I also came to realize that its most probably the torque converter clutch dragging slightly when cold. I did read about an outfit that actually split a MB converter and added some springs to the clutch mechanism but never knew that CVC made them commercially.

__________________
2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

Sonnax makes the parts for the fix of problem in the Torque Converter, and CVC uses the Sonnax fix in all their re manufactured torque converters.

Read the "related tech resources"

722.6, 722.9 - Sonnax

Read pages 5 through 7 on the notes of the CVC section

All the best,

Martin

Attached Files

CVC Mercedes Torque Converters.pdf (490.8 KB, 739 views)