Got a hand me down of a 2010 GLK350 4Matic with about 56,000 miles last winter. When I first got it, I noticed some shuddering when turning full tilt, but didn't think much of it at the time - chalked it up to just the nature of an 4WD system like what was on my jeep (how wrong I was). When the spring/summer rolled around, shuddering went away completely.

Two weeks ago I started getting some hiccups when accelerating at low RPMs (starting around 18mph), and noticed that the tachometer would dance up and down a bit... utoh. Thought it could've been an engine misfire or spark plugs, but no CEL.

The next day the shudder turning came back, and the day after it was back with a vengeance... felt like the back was going to fall out just from normal turns during driving. I did my research and discovered all the issues with the transfer case and the 722.9 transmission.

Brought it to an indie Mercedes mechanic, and prepared for the worst. He changed the transfer case, front, and rear diff oil to start and there was instant relief. Not back to driving as well and smooth as it was this summer, but back to what it was like last winter.

I've ready people who have had some success with just a fluid change, people who temporary relief, and those who had to end up getting a transfer case replacement. I wanted to see if those with GLKs have had any updates on their experience with the TC, and what advice people may have for this situation. Is the shudder itself dangerous, or just a sign of worse things to come? Or will I be able to get away with things as they are now, and just have to deal with the vibration (which I can live with)?

We're considering selling it while we still can and getting something with cheaper maintenance. It'd be a shame, though, as I do love the GLK. Thoughts?

 

 

I'm not sure I quite understand: you said the indie mechanic "changed the transfer case..." so if that was the failing component and it was replaced, what else is causing your shuddering?

Are you contemplating a complete tranny rebuild? Has your indie checked the front diff U-joint connecting point to the transfer case itself? Those joints can go bad causing the shuddering and also can grenade the TC itself.

I've had the fluids in my tranny, diffs and TC replaced at 60K miles just to be safe, but there's no guarantee that a component won't fail at some point. That's the nature of mechanical beasts I guess.

 

 

@Van Ha Nguyen Correct, and that makes more sense since the TC is basically housed in the transmission and shares the same fluid. A little clarity never hurts.

OP: I agree with VHN: you are likely looking at ticking time bomb scenario. Deal with it sooner rather than later, because it will be an expensive pain one way or the other. Maybe just cut your losses and move on.

 

 

Good advice to check it periodically. I wonder how often it gets checked, what with most oil changes being done top-side these days.

I get under there.

 

Do you mean "front axle" rather than "passenger side front axle"? since you have the 4-matic the output of the transfer case is two shafts, one going forward and one going rearward.
Each of these two shaft goes into another differential, the front differential has the two front (drivers and passengers side shafts) connected to it.

If it is truly the front passenger side shaft, then the leak is in the front differential, quite easy to add oil, use synthetic 75W90 oil, to top it off. The correct level is when it just starts overflowing out of the fill plug. if you have never changed the differential oil, this is as good a time as any, open th efill plug first...then the drain plug, close drain plug, and refill.

The transfer case is bathed in the same fluid as the transmission. Checking the level should be as easy as looking at the dipstick Wait....did those dips*** forget to design in a dipstick ?????? so only the dealer can check the level and add fluid if needed???? that really sucks.

For the not so faint of heart, and more experienced.....raise the car up two feet, keeping it level. Start the engine and let the transmission warm up to 140F (use a good code scanner or shine a temperature scanner on the bottom pan) . While the engine is running, remove the drain plug. If fluid trickles out, the level is correct.....if no fluid trickling...pump in a bit of fluid until it does...

 

 

Are you talking about the boots split and grease coming out? That's totally different than leaking TC or Diff. Btw, some sweating on either TS or Diff is normal per WIS. My dealer said it was leaking...it's been like 3 years since, and not a drop. F dealers.

Also, it's not fully correct: TC is not fused to tranny. In fact the seal between TC case and tranny case is what leaks.

 

 

the very slow leaks with black "crud" building up is very common in older cars. It slowly gets worse....and eventually requires a seal change...but actually this can take one or two years. I noticed this on my rear driveshaft seal coming out of the transfer case when i did my transmission fluid change last year, but the amount of crud was not enough to worry me.

If you prefer to be proactive, go ahead and change the seal...it it is a very small amount of crud....you have some time on your side.

 

So is this collection of crud on the diff side of the axle or on the wheel side of the axle? Some pics would be best.

EDIT: I re-read above, sounds like it's coming form the front dif. But are are you talking about "crud" on diff or the axle? I'm not sure how you can see anything on the axle.

 

if i have an ELW will transfer case issues be covered? 2015 GLK is approaching 50k miles and i'm planning on adding an ELW to stay safe till 100k

 

Hey man, what ever happened with this issue? Still own the car?

 

Updating this thread with some of my results.

I took the car in for service today. They said they've seen this issue before, and it's not unique to the GLK / C-class. Apparently they see it with BMW's too. Specifically, the "hiccups when accelerating" issue is related to the torque converter. They preformed a transmission flush, and reset the transmission computer. Something to do with it self calibrating and re-learning. Maybe over time, with old fluid, it's gets its wires crossed. The "shuddering when turning" issue is another issue and related to the transfer case. They have reset procedure for this as well which, from what was told, involves driving around in circles a few times lol.

 

Hey Ryan,

Having the same issues with a shudder when accelerating and a shudder when turning on one side only. Any updates on your side, did the dealers fixes work and can you confirm what was done? Thanks

 

Hey, happy to say my issues have been fixed.

Issue 1 - shuddering when accelerating - as mentioned this was apparently caused by old transmission fluid. My indie mechanic preformed a transmission flush which so far has fixed the issue.

Issue 2 - vibrations when turning - a fix was attempted by my indie mechanic where he drove around in figure 8's in a parking lot. This was enough to fix the issue long enough for me to drive home. The issue came back fairly quickly. They quoted a new planetary housing (~$1000).

I figured I'd try taking it by the dealer as I heard some owners were getting their transmission replaced out of warranty. The service manager knew exactly what the issue was, guess its quite common . He quoted me about $75 for the repair. Whaaaat. He mentioned the issue was related to the clutch plates in the transfer case binding together over time. His fix was to take the car on the hoist, manually block off 3 wheels at a time, and let the transfer case send power to each corner. This opens up the clutch plates and let's the fluid get in there un-binding them. It's been about 2 weeks now and the issues hasn't come back. I'm guessing I'll have to preform this procedure at the next 60k mile interval.

 

Wow Ryan!

First I cannot get over a $75 labor job at the Stealership haha! That's encouraging news, thanks so much for taking the time to respond so quickly, there is hope for me, was literally thinking I cannot invest a new tranny in the car and should just sell it off for cheap. I will flush out my transmission, replace the oil, filter and gasket and hopefully this takes the shuddering away as it did with yours. Cannot thank you enough I was scared to dump anymore $ into the car with either a new torque converter or new tranny. Will at least try your solution with confidence, even if it doesn't work it's now worth a shot before that big $ fix.

Thanks again,

 

Ya, no problem. Let me know it it goes. Good luck 🙂

 

Not knowintg too much about the MB Transmission, if any of the issues with them have anything like most automatic trans, some times clutch plates get a coating on them which under physical inspection would remind you of coating them with STP Oil Treatment thus a slippage occurs. I have owned a few vehicles that were cured of this by using Lucas brand Transmission additive, when used it disolves the build up of the clutch plates which are what may be the shutter/slipping, and it conditions seals and other internal parts..I used it on a Ford F 350 that started to shudder under even a slight load or going up a slight grade on the road and it resloved the issue which never came back after over 135,000 miles of hard use. It saved me from having to purchase a new Transmission. Used the same additive to cure an issue with Escalade that was slipping and long shifting from one gear to the next. It does work.