martz

BUMP!!!!!

Been searching for answers, I figure I revive this thread.
Anybody know for certain what causes the clunk/tug on the rear end?

I have noticed on mine it only does it when not under load,( foot off the gas)
essentially while coasting at slow speeds and then when transmission shifts the jab sound resonates from the rear. Normal/spirited driving transmission shifts like butter.

Hoping its just a mount, flex disc and not TC.

fju2112

Seems to happen to enough people that it can be considered "normal", I guess, unless anyone here has had serious tranny problems in conjunction with this symptom? Thanks for bumping, Martz!

fju2112

Ah, mine got totaled!! I miss that 8-cyl power. With gas only at $3.80, I really miss it. Seriously, I never would have considered selling it even at $4 a gallon.

I have heard great things about EAS from some of my father's customers (he owns a business on the same street). I go to Accel on Linden Street because of the relationship my father built w/ them when he owned an Alfa 164L back in the day; they used to do work for Alfa when they were right next door to that DD/Petco/CVS plaza. Do you live in Waltham, Boston? Have I asked you this already?

joe maniqz

same thing happens with my bmw 525...it happens when the transmission is downshifting while you stepped on the gas, i think the trans just got confused and it just skipped a gear to upshift...i'd hear a loud thud and lose power for a second and everything would be back to normal operation...my car seems ok after, happens everytime, car still normal.

91300e

i get rough shifting from my 4matic also (91 e300)

Figuero

I have noticed on mine it only does it when not under load,( foot off the gas)
essentially while coasting at slow speeds and then when transmission shifts the jab sound resonates from the rear. Normal/spirited driving transmission shifts like butter.


I have the same symptom - always under light throttle especially right after coasting at slow speed. 90% of the time it is an upshift but I have felt it on a downshift, but never under any kind of spirited driving. I'm of the opinion it's the rear differential putting some slack in the drive train.

I had something similar in our old '97 but that was directly related to a delayed and hard 2/3 upshift under light load - turned out to be some kind of sticking valve in the tranny. It felt like it was just banging into gear.

martz

I bought the wrong model ! Wonder if non 4 matic E classes have this issue?

Also, how can Mercedes Benz call this "Normal"? Well the dealers have, from what I've read.

fju2112

Since the transmissions in these cars are generally long-lasting and reliable, I don't think it's a symptom of a major problem since so many owners tend to have this issue. You have to consider that the shifting is computerized and changes w/ the driving style in this model, and as far as I know this is one of the first benz models to have such a transmission, so maybe it's just a kink that got worked out in the w211?

martz

Then what is that KINK? I would want to know, wouldnt you? maybe its a simple fix, maybe not.........

ohlord

the transmission fluid ,filter and transfer case fluid and rear diff fluid.
the kink lies in the lifetime fluid claim that benz came up with for the 722.6 trans.Now they say every 39k miles.
mb fluid only.Diy on benzworld.org w210 section and mercedesshop.com
if anyone reading this has a newer model without the trans dipstick tube they can't do the diy,as it takes a special machine to fill the trans via the vent tube located on the pan.
A 4matic should be seamless in shifting,fluid change will help and resetting the tcu via the trans adapt feature will also help a bit.
ohlord

SLOPESTAR

Same klunk here on my 99 4matic wagon. it just seems like i feel it when going from braking ti back on accelerator. It is subtle as stated by others. I have just performed the 100,000 mile "tune up" and had all the proper fluids replaced or topped off/checked etc. Its still there but she purrs like a kitten and there were no leaks from anything. I took it to Jeff at OC Benz in Costa Mesa CA. They treat you right!
Also had front and rear suspension done on the 92" 190e/front brakes and rotors/belt and tensioners/fluids/filters and a few other tweaks. $1500.00 and well worth it as the car feels like new. It is amazing that a 16 year old car with 160,000 miles just keeps on going and looks great too. Here in So Cal, there are so many exotic/luxury cars and still you see 190's everywhere. Mercedes owner for Life. Buy them used and maintain. They will last and last!

ohlord

but have you had your trans fluid and filter changed.1999 had a torque converter drain so you can drain almost all the fluid.Per the diy.Or your trusted indie can do it

martz

I"ve done that, including draining of the Torque converter
Transfer case is sealed, there is a fill plug but no drain plug and mind you it's a Mercedes!!!!
Rear diff was serviced !
Front diff is sealed!
According to my mechanic my flex disc, trans mounts, engine mount's look good. I am still hoping that maybe the flex disc may look good , but still could use an R & R which is what I am going to try eventually.

The kink does not lie on the fluids. As much I respect your knowledge on these cars, I have to disagree with you on this one. It's more than just a fluid change. Look at this thread at 15k miles he had the same issue. Problem found was engine mount was bad or so they say......may have to try that too.
Another said Planetary gears on the TC....OUCH!!!! dont like that!

http://www.benzworld.org/forums/w210...20-4matic.html

ohlord

saying in all cases ,but at 100k miles if a 722.6 is shifting poorly a fluid change is in order,sooner than later
your case sounds like something entirely different.
722.6 transfer case fluid can be changed and mercedes on the later model 722.6 states at 39k miles.Maybe your indie does not have the tools to do it?Several members have changed their transfer case fluid,don't know why yours would be any different.They suck it out.

I hope they find your problem before it gets worse

SLOPESTAR

yes ohlord. fluids a nd filter was changed. definitely trusted indie! always great advice and follow up from you!

martz

TC... They suck it out! .. any threads you can point me to , for specifics? Can a manual extractor accomplish this? Or must it be one of those sophisticated ones. My indie was looking for a drain plug. ( I also assumed there was one) Heck, I only found out there is a fill hole by searching through benzworld and from what I've read its not really that easy to get to.


BTW I have 85k on the clock. I cant say that it shifts poorly, more like a flaw within the 4 matic drivetrain. Are you implying that fluid change is the fix?

ohlord

that is a tough call.The service sheet calls for fluid change at 39k ,and it is a B to get to.Give me about a week and I will get you a diy or more info.I am going to be dropping one with a local member sometime in the next week or so.
Have you reset the trans control?

Franasia

I’ve been experiencing this problem ever since I bought my 4Matic almost three years ago.

Clunk occurs when the car downshifts into first gear as you're rolling to a stop. I found that by switching transmission program into W mode permanently helps a lot. You don’t get to hear the clunk that often.

There are a few threads on the forums on the topic but for some reason word never spread out as to the cause and fix of the problem, which has been posted only a couple of times without any major public reaction. See:

http://www.benzworld.org/forums/w210...-e320-awd.html

https://mbworld.org/forums/showthread.php?t=72671

This is the fix:

Slack in the planetary gearset: the recommended repair under TSB AF28_10-U-1600AG is to replace the planetary gearset with a friction plate.

Hope it helps.

Cheers.

91300e

lucas oil makes a tranny fix that stops hard shifting and such maybe you should try it, idk it couldnt hurt or anything

sosh

Yes it could do some damage!! Most trans additives are snake oil and can cause irrederable harm to the transmission.

91300e

well i got nothin else since my idea was shot down no jk but um good luck with it

martz

I reset my TCU and you know what, the clunking, slight jolt has disappeared. I hope I am not jinxing myself. I also can not correlate on how and why.
Logic points to the driveshaft and is surrounding parts. Or worse case scenario TC.

Ohlord ....thanks for the tip.

dieter.boehm

Martz: How did you reset the TCU??

raymond g-

for models with electronic, adaptive transmissions:

1. Turn the ignition key to the on (not start) position.

2. Press the gas pedal to the floor and hold for five seconds.

3. Turn the key to the "off" position (don't remove the key), then release the gas pedal.

4. Wait at least two minutes for ECU to reset.


use the SEARCH feature to review past posts/threads

dontbirdme

So is this as simply as a transmission reset?