Mercedes-Benz Forum banner

High milage 722.6 wear questions (MAVA my lord and savior?!)

6K views 20 replies 6 participants last post by  Kajtek1 
#1 ·
My 05 E320 CDI with 443,000 miles is still running and driving great, but my transmission has always never shifted quite as nicely as my dads 06 E320 CDI. There's no noticeable slipping, no serious shifting delays, BUT i am detecting a bit of an issue with the behavior of the torque converter. Sometimes when accelerating at low speeds in a high gear (low RPM's high torque) the torque converter doesn't feel like its grabbing or "transferring torque" quite as well as it should. I can hear the turbo spooling and the engine revving, but the car intermittently doesn't accelerate as quickly as it should. Again, The experience is NOT slipping, but something else as the car still does accelerate all the time, just sometimes not quite as quickly. almost as if the lockup clutch is not locking when it should.

Second issue, is under hard acceleration between 2-3, i get a HEAVY wub-wub-wub vibration/smacking right under the center console when the engine is at peak torque. it feels as though the vibration is 'muffled', as though its being dampened (By rubber mounts perhaps?)
I've replaced or checked every component post-transmission; driveshaft center support, flex disks, engine and tranny mounts, etc. The vibration definitely feels as though its coming from the transmission.
a similar vibration i feel coming from the same place accelerating at any rate between 3-4. its a light vibration, but it vibrates the whole car noticeably to feel in my butt. i believe these two acceleration problems are connected, possibly related to the torque converter issue? maybe a main bushing failure? (transmission fluid has always been quite nice looking after every 30k mile trans flush. no signs of coolant intrusion. Radiator has been replaced before i got the car, and then replaced again last year after a minor front end impact.

I noted a while ago in another thread that on my last transmission flush, i had tiny copper/brass looking non-ferrous shavings in the bottom of the pan and the filter. A few of you remarked that they are most likely to be from the friction material, but more unlikely COULD be from bushings.

Due to the high mileage, i was basically just planning on just continuing 'as normal' driving the car, and just plan on completely rebuilding the transmission and replacing the torque converter when something finally fails.

ALL of these problems have been present since i bought the car 3 years ago, and haven't noticeably gotten much worse since then. What do you guys think? Any suggestions on what to look at or if i should rebuild the transmission BEFORE it blows up? :D
as usual your input is much appreciated.
 
See less See more
#2 ·
When MAVA sure is expert on those transmission, I would suggest sending ATF sample to the lab. I am using Blackstone.
On other hand my $100 scanners allow for monitoring transmission gear changes and slippage during driving. Did not get to it yet, as I have no complains, but the option is there.
 
#3 ·
I am going to do a Blackstone analysis sometime soon, as I'm going to do an engine oil analysis as well.

I have monitored gear shift change times in star before, and there was very little time between "target gear" and "actual gear". MAVA let me know about the adaptation values and how that's a good indicator of transmission health in a previous post, and none were even close to the low or high limit values in either fill time or pressure when I carried out the test. (I would have posted results, but was in a hurry that day and didn't have time to take screen shots.)

I had a feeling the adaptation values would be fine, given that the transmission doesn't really 'hang' between gears at all, and resetting the adaptation data doesn't really drastically change the way the transmission behaves. I have NOT checked them since I reset the adaptation values though, I'll do that tonight.

To me it feels more like an issue with the torque converter. Either with the locking clutch friction material itself, or with the valve body.
The shift quality doesn't quite feel as quick and tight as on my dad's CDI as I stated, but his has less than half the milage. I just attribute that to valve body wear, and it's nowhere near what anybody else would consider a 'problem'.

Sent from my SM-N950U using Tapatalk
 
#5 ·
Only one of the most magnificent mercedes transmission experts known to man that lurks with us mortals on the forums.
We really don't deserve him.

Sent from my SM-N950U using Tapatalk
 
  • Like
Reactions: MAVA
#6 · (Edited)
My car is exhibiting same issue of mysterious friction noises that appear to be coming from transmission somewhere under center console during cold start warm-up runs. Shifts from 1-2 & 2-3 in Sport mode actually remind me of a bouncing ball as car will surge & coast (ebb & flow like ocean tide waves) after shift to higher gear during gradual accelerations to 25mph or so until coolant temperature reaches about 80 C. A recent ATF flush revealed aluminum in pan & brown fluid after 30k miles. I haven't replaced flex discs on driveshaft yet & have theorized these to be suspect. Best case scenario that I picture occurring is flex disc's gradual fatigue wearing down to act like a springy coily torsion bar on driveshaft right after shift until speed of it catches up to new load demand & smooths out. I actually had a flex disc fail in a previous car. When it came apart it's disintegration reminded me of a baseball that loses it's outer jacket skin to reveal a bunch of tightly wound rubber bands peeling & unraveling away from each other. It's either those flex discs, TC, or a sleeve spring in valve body but since the latter 2 are rather labor intensive to replace or directly access to inspect, I will eventually replace 1st the flex-discs & hope I don't have to change out driveshaft center-bearing as well although likely I will have to replace it too truth be known which will make that job almost as labor intensive as exhaust pipes & mufflers will have to be dropped out of the way to get access to it. DAS hasn't stored any codes related to transmission yet & CC still works nicely. Adaptation resets tend to cure issue for a little while but eventually bouncy shifts return when ATF & coolant are less than normal operating temperature. The friction noises are most noticeable when I accelerate in 1st & then back off the throttle just prior to upshift & allow car to coast to a stop. The friction sounds I hear resemble a spinning lathe that is whittling away on a pipe that has run out or a warped brake rotor that is intermittenly & unevenly contacting brake pad with light braking. I definitely suspect those sounds are coming from TC. I've been thinking about securing a go-pro or cellphone to bell housing to see if I can catch some of those sounds on video live & direct to identify & differentially diagnose it further but for time being I'm just carefully driving the car like driving Miss Daisy until it warms up so as not to rock the boat too far to tip it over. Once it's warm, car shifts smooth as butter regardless how hard I push it & still gets 30-35mpg on highway commutes so I count my blessings & just monitor the situation until something more sinister starts manifesting.
 
#7 ·
Who performed the “flush”? This trans takes 8 quarts, but I end up wasting an extra 2 quarts to make sure the fluid is fully replaced in the TC and cooler when its pumped through. Was the pan dropped? Magnet cleaned? Do you have a MB dipstick to check the level? A140589152100 $23 at dealer, this allows you to check the level and color. There are shops that don’t bother dropping the pan but just suck the fluid out the dipstick tube and half of the fluid can still remain in the TC.
 
#8 ·
I did an actual flush by popping off the trans cooler lines from the radiator. I flushed a total of probabaly 10q through when I FIRST got the car. Since then, every 3 engine oil changes, or approximately 35k miles, I drain the pan, change the filter, clean the pan and magnet, and refill with the right amount of oil to top it off to the full mark on the dipstick at 80°c. I see no need to do a complete flush every 30k.

Sent from my SM-N950U using Tapatalk
 
  • Like
Reactions: MAVA
#9 ·
Here's the results of the adaptation values in STAR!
according to STAR, "if the filling time and shift time are at the adaptation limit, the adaptation values of further gearshifts may be increased."
"If the adaptation values are reached, this indicates a fault in a hydraulic shift element."

"If the filling pressure adaptation values limit is in positive display range, there is damage in the automatic transmission."





Sent from my SM-N950U using Tapatalk
 
  • Like
Reactions: ezzo
#12 · (Edited)
Here's the results of the adaptation values in STAR!
according to STAR, "if the filling time and shift time are at the adaptation limit, the adaptation values of further gearshifts may be increased."
"If the adaptation values are reached, this indicates a fault in a hydraulic shift element."

"If the filling pressure adaptation values limit is in positive display range, there is damage in the automatic transmission."
Lets get the theory straight :nerd Not really theory, but practice in using this info from STAR which is beneficial from outside the transmission.

Any positive number is "wear percentage". When the transmission is new(made well, or gaped correctly at the friction packs) the wear value when new will be "0". As the transmission accumulated mileage increases if you are lead foot driver. The increases at a faster rate. The cap is "15" which is very wide, but the critical clutch packs are K3 and B1. Now, B1 is reading negative. i have no clue why, but every 722.6 I have opened B1 has a large gap in the frictions-meaning wear of friction material. This is normal of any 722.6 transmission... B1 is for the early gears, and K3 is for mid to late gears, but K3 will start to grind away the inside of the K3 housing with excessive wear, and that I have seen a few times... Here is something on it:

http://www.benzworld.org/forums/w140-s-class/2212242-handy-way-determine-how-worn-out.html

What I would do in your case :nerd

A) I would pull the valvebody down, and see how malleable the o-rings are on the shift solenoids and torque converter(TC) solenoid. I know the TC solenoid will be brittle hard, but the others I have no clue, and they must fit a little tight not just fall in the hole, and those o-rings Mercedes DOES NOT SELL THEM :crying .

B)I would lift out the black regulation solenoids out and clean out the screen filters, or replace them(Mercedes sells the screen filters). See the pictures from this post...

http://www.benzworld.org/forums/w21...ve-body-rebuilt-transmission.html#post9558858

C) My guess is your regulation solenoids(The black ones) are getting tired too, and they are about $250 each :crying , yet in your shoes. I would find a late model +2000 722.6 car(any S, SL, C, CL, etc...) at the junk yard, and buy that used valve body with solenoids, and that may set you back $100.00 or less. Swap the whole thing out...

https://www.lkqpickyourpart.com/locations/

Row52 | Search Results

The used valve body may be worth your gamble...

D) Do inspect the conductor plate speed sensors with a magnifier for hairline cracks that the naked-eye cannot see as you may be on the onset of a worn-out conductor plate too..

E) Check your shifter bushings too...

I would do that first over anything of replacing/rebuilding

Martin
 
#10 · (Edited)
It really depends on the color of your fluid and the smell on whether or not a full flush is warranted because dropping the pan only gets half of the fluid, and the fluid left(4qts) contains oxidized fluid and if its broken down (not providing lubrication) then you are essentially wearing out your tranny faster. It would be better if you did a full flush every 4th oil change or 5th if the color and smell are good. Putting in new fluid into old which is a 50% dilution is harmful. Old fluid affects the rubber seals too. You see the problem you are creating by only half filling the tranny with fresh is that you won’t be able to judge the remaining life by color and smell. You are not rejuvenating the old fluid in the change. Those molecules are just getting older and older, broken down and worthless, contaminating the new fluid and and shortening the life of your tranny. Ravenol M6 series 236.10 was $14 per qt shipped in October 2017 and you don’t need a funnel, each bottle has a tube spout that pulls out fits right into the tranny dip tube, No spilling or dripping!!!
 
#13 ·
This is why I didn't just PM, this information is much more valueable in the open, especially since these transmissions are so widely used in all MB Platforms of the era.

I was definitely planning on "rebuilding" the valve body before I even thought about pulling the entire transmission.
As for the solenoids, what about these EBAY sellers that sell 'remanufactured' genuine OEM solenoids? Like this seller for instance, hes out of Texas, 99.6% positive feedback, they're guaranteed to work, come with a 1 year warrenty, and you get a tasty looking set of 6 for $68. My guess is that he's just pulling them from junkyard valvebodys, testing them, and then reselling.

https://m.ebay.com/itm/Genuine-722-...d=p2385738.m4383.l4275.c10&_mwBanner=1&_rdt=1

As for those O-rings, are they a fairly common metric size? If not, does anyone have dimensions or a possible aftermarket source?

Lastly, if I'm going to be digging into the valve body, do you think it would be worthwhile to remove and inspect all the springs, pressure regulators, end plugs for play? I can get a Sonnax valvebodys rebuild kit like below, or do you think it's not needed, as that would cause other shifting issues?

https://www.ebay.com/p/Zf6hp21-Tran...%26rvr_ts%3Deea4b10f1630aa4938259b94fffb28d2&



Sent from my SM-N950U using Tapatalk
 
  • Like
Reactions: Noodles
#14 ·
I meant that "can you comment on my post?". I do not go trolling onto other forums for fun. I personally do not like to have "fix-it and repair-it" one on ones as I'm busy like everyone one else. I will answer as I can....

On the solenoids, you want some from +2000 cars. something with not to many miles as heat kills everything, and in a hot state(like Texas) one can say the solenoid(s) are more tired than coming from the East Coast... You do not want some 90's solenoids as those will just will be really tired.. For $70 it is good deal.

With these solenoids at face value they will always "Measure well" electrically with a meter(the ohms), but the real test is oil in hot conditions. I seen these fail under load where the TCM will never register open or shorted conditions, but they fail due to the magnetic field collapsing due to heat, and heat changes the magnetic saturation curves, and with time it will collapse(not work). Big problem with rear-earth magnetic motors (or any motor with magnets). The curie-temperature goes up to the point, and the magnetic field disappears( our case the solenoid fails ). Same reason you want your "Hybrid" or "Electric car" with an induction motor not a permanent magnet motor for that same reason. I believe one American car company was making permanent magnet motor for one of its hybrid cars(all I can see Economic Obsolescence ).

The o-rings. In my second link you can see the baggie of solenoid o-rings in one of the pictures.Those o-rings came from 722.6 rebuild seal kit which contains all the seals for a 722.6. The kit is like $130.. I bet you can size up the o-rings, and find them online like this guy did for his solenoids-post 13:

http://www.benzworld.org/forums/w14...722-6-transmission-computer.html#post16973138

You could open your valvebody, but I think it is just wiser to get any +2000 junk valve body with the solenoids for less than $100. At $400 or so you can get a rebuilt from Mercedes, but I would not go that route yet. A Sonnax rebuilt is like $1200 with updates.

MB Valve Bodies Mercedes transmission parts

The Zf link is not the same for the 722.6. It is a whole different beast...

Here is the Sonnax info:

https://www.sonnax.com/units/211-722-6

Click on the yellow radio button called "Valve Body Layout"

I have bought from these guys:

Mercedes transmission parts,TransmissionpartsUSA.com

Martin
 
#15 ·
Following with increased enthusiasm... Question: Was this transmission used in any vehicles besides MB's? I seem to recall a video on YT where a transmission tech was tearing down a early production Chrysler model 300 & it having a 722-6 variant I think. If same, would certainly increase salvage yard prospect pool for parts like valve body, solenoids, & control units.
 
#18 ·
Yes it was. Chrysler used it in a few applications. They called it the "NAG-1".
That was my next question.... Are the valve bodys between Chrysler nag-1's and the MB 722.6 interchangeable? I can find oe chrystler application valve bodys cheaper than MB, and they tend to have lower milage as well.

The case is different on a "Chrysler 722.6", but the two-seater Crossfire is a W210 facelift E-Class, so it has all identical parts as a W210-Mercedes engine(M112), 722.6(second gen trans), suspension parts are identical, and differential. All those parts will fit a W210, or the early W211's for engine and transmission.

The jeep commander / Dodge Charger and Challenger have 722.6, but the case is different, and something mechanical is different on the valve body because of the different case. The oil pans are not even close. The internals of the 722.6 of a Chrysler are the same as a Benz.

I would just find MB cars. ANY MB +2000 S,C, E,CL, SLK, and M with a TOUCH-Shift Shifter car.

Martin
 
#16 ·
Yes it was. Chrysler used it in a few applications. They called it the "NAG-1".
That was my next question.... Are the valve bodys between Chrysler nag-1's and the MB 722.6 interchangeable? I can find oe chrystler application valve bodys cheaper than MB, and they tend to have lower milage as well.

Sent from my SM-N950U using Tapatalk
 
#17 ·
This is not a super urgent issue for me, I'm planning on putting a lift in the barn next month, and that would be super handy for this job. When I get to that point, I think the first thing I'm going to is just drop the valve body, teardown and inspect everything, clean and reinstall with fresh oil. I have a feeling with all these miles accumulated, that those solenoid screens are going to be plugged and O-rings are going to be shot. So I'll start there. I'll report back in this thread once that's done. :)

Sent from my SM-N950U using Tapatalk
 
  • Like
Reactions: MAVA
#20 ·
She drives a Benz like the rest of the family. I now have 6 benzes to keep up on maintence with.
if she wants to keep her CLK, a lift is going in the barn. [emoji23]

Plus I'm doing all the work myself, so it's significantly cheaper.

Sent from my SM-N950U using Tapatalk
 
  • Like
Reactions: hangit
#21 ·
I bought this lift https://www.amazon.com/TRIUMPH-NSS-...=UTF8&qid=1529175975&sr=8-3&keywords=car+lift
a year ago and now wonder how I did so many car repairs in all those years without one ;)
In my case strong point was that thanks to 10' ceilings, I can park convertible and sedan in single garage space, but it really puts different perspective on car repairs.
To top it, lift is rolling on its own wheels and guess what I used to unload 2-tons garden sculptures?
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top