slim nicky

Last Sunday (11-16) my 2008 GL550 started suddenly downshifting for no apparent reason. It would suddenly downshift regardless of speed to a low gear, and at other times feel like it was coming out of gear (rev high and lose power) and then downshift. I had no prior issues with the transmission and in fact have been impressed with responsiveness and smoothness.

Had the car towed to MB Dealer same day where it still is. Initial diagnosis by dealer was that there was something wrong with the second gear and that downshift would occur from third to second gear. After discussion with techs in Germany they tried changing "the controller" of the transmission thinking issue was with electronics/software. When this did not work they concluded issue was with hardware, so discussed replacing second gear, but went with replacing the entire transmission unit per Germany's advice. I am now told that they have replaced the transmission unit and the control unit with new ones. They have run tests and confirmed that the components work separately, but that they cannot establish communications between the two. So the car does not start, and if/when it does, they cannot shift it into gear.

This is so frustrating and disappointing! It was a total bummer to have the transmission go out, but it is downright depressing that the dealer is not able to make the repair! Don’t know what to do. Has anyone had a similar experience?

I am printing WA State Lemon Laws tonight, but I am really hoping not to go there. Related – still have unresolved issue with suspension clacking noise made going over speed bumps (see https://mbworld.org/forums/gl-class-...peedbumps.html). Has anyone had luck with that?

Depressingly yours,

Slim Nicky

MoMocedes772

File it as a lemon if it does end up applying to the issues you have stated. The 7-speed auto has to be the worst transmission my right foot has ever pushed.

MomsBenz

Any news? I can honestly feel your pain. I hope they get it fixed and back to you soon!

Fifth Ring

Honestly, the more I read stories like this the more I am convinced that a dealer network is simply not up to the task of fixing certain issues (transmissions being top of the list). Car makers need to establish a program where they either plug-and-play a whole drivetrain, or swap in a new or refurbished car of equal or greater value. Alternatively, we just rent cars per-diem and just give them back when stuff like this happens.

MKW

I think part of the tranny issues is the deliberate calibration trying to max MPGs. We complained about occas jerky downshifting in low gears . They reflashed with new shifting software algorithim. Car shifts smoothly now - BUT - it's because it holds lower gear longer at light throttle up or down depending on whether you are slowing to a stop sign or slowly accelerating from one , so in town MPG has dropped a bit.

Fifth Ring

I went through hell with an Audi automatic. Replaced a valve body, then the tranny. Then the technician thought it was the TCU (computer). Then some communication between the ECU and TCU. I finally traded it in to an Audi dealer. I still see the car parked outside a local mattress store. I'm tempted to go in and find the owner, but then again, maybe not.

blittle

Conversely....with my 2007 450GL, the 7-speed is probably the SMOOTHEST, most problem free transmission I have ever owned in 40 years

dieseldoc

Ihope that your GLIs fixed soon. I have had zero issues with my transmission.

slim nicky

They finally fixed it, and it is working perfectly. Very smooth shifting up and down. The description of what they did runs 7 pages long, and it looks like they tried just about everything to get transmission to communicate with the control module. What ended up working was disconnecting the battery and rebooting (yes rebooting!) the car. This apparently reset the errant signals from the prior transmission and established communications. I drove the car over the long weekend, and was told to return it on Monday for a check-up. Signal wise everything checked out (tranny and shifting is fine), but they found fluid seepage on an axle boot and had to repair. Apparently there is a lot of work involved to get to the tranny, and they needed to disassemble a whole bunch of things. Paper work for seepage indicated that they actually had to weld a part together to stop seepage.

Anyway, everything seems to be operational for now, but I am concerned given the majorly intrusive nature of this repair. Meanwhile I am collecting paperwork for Lemon Law. I really hope it does not come to that, especially since I am coming off a negative MB experience with my prior vehicle - 1998 ML320 (sigh). At least I'm feeling better now about the extended warranty I purchased.

As an aside, dealer told me total cost to MB will be about 18K (all covered under warranty of course for me).

My experience I think provides evidence to Fifth's original observation that dealers are just not equipped (technical knowledge, know-how, and parts) to do certain kinds of maintenance, and that there has to be a better way (maybe a regional repair shop where they ships cars to get repaired if it is certain things, or travelling expert repair crews?).

slim nicky

MoM - Why do you say that? What do you mean? I have been very impressed with smoothness and adaptability, albeit not reliability .

dieseldoc

I agree with slim nicky very smooth transmission and my vehicle is a cdi. no complaints. I am very happy they got your GL fixed.

N'AWLINS

I agree with MoMocedes....worst tranny ever in any M-B I have owned. My
'08 320CDI has been re-booted, re-flashed, re-learned, re-valve bodied, etc. etc., etc. Still feels like someone runs into the back of me at every stop (harsh shift from 3-2). Next trip to dealer is to meet the Zone Service Rep. They have helped me enormously in my 30 years of M-B ownership.

slim nicky

I wonder why there are such variations in experiences. This combined with reliability issues really makes me question whether MB is back on track and whether we can build cars in US.

HJZ06

Our GL450 tranny started to act up last week. Would not disengage at stop then would remain in a higher gear on acceleration. I stopped, shut off engine and restarted, would not get out of first gear. Let sit for 1/2 hour and worked fine! Has popped up a couple of times this week, waiting for dealer opening with holidays. First time in 32k.

oknish

FWIW - many recent TSBs have popped up on tranny issues.

slim nicky

Sorry to hear. Sounds like what I had, execpt for mine did not work after sitting. You may need need valve body at a minimum. Please let us know how it works out.

Fifth Ring

I'm willing to bet that the drivetrain comes to the US from Europe fully assembled, and it's basically plug-and-play. That said, I also wonder about the wide variation in experiences.

My other MB (2002 C32) has a 5 speed auto that has worked well for me, but other C32 owners have had endless issues with rough shifting. And AMGs are ALL made in the Fatherland.

And, for the record, the transmission on our GL320 has been flawless. Given the narrow power band of a diesel, the 7 speed transmission is a perfect match. My only "complaint" is that the manual gear select buttons on the steering wheel are useless and needless. I suspect that my wife has no idea what they do, and probably has driven many miles with 6th, 5th or 4th gear manually selected.

BlownV8

Wow, they make the ML63 AMG completely in Germany? I would think they would use the same plant in Alabama where all the other ML's and GL's are made.

am_beagle

In Alabama, they assemble, not make. Especially for engines and transmissions.

jhcicco

'My only "complaint" is that the manual gear select buttons on the steering wheel are useless and needless. I suspect that my wife has no idea what they do, and probably has driven many miles with 6th, 5th or 4th gear manually selected.'

I agree. Manys the time, I've been grasping the steering wheel, squeezing it in time with the music I'm listening to and downshifted. Makes for an interesting ride.

StevethePilot

I replaced my MB Tex factory steering wheel with a wood-n-leather one from eBay. When it was installed, I went from one side downshifting and the other upshifting to the inside of the buttons is downshifting and the outside is upshifting. Haven't had an inadvertent shift since. I wonder if that's something that can be set or toggled by your SA?

The one and only time I found the idiotic flappy paddles useful was when the turbo hose popped off and I had to manually shift in order to exceed 12mph because the computer couldn't seem to compensate.

STP

Comfy_Couch

Can anyone shed some light on how these things are supposed to be used? I get the sense they're not the same as the "sportronic" type manual shifting setup you see in other vehicles, but I'm still not sure what they're supposed to do.

StevethePilot

My best impression of them is they're there to make you feel like you're driving an expensive German car with flappy paddles. And to allow you to select which gear you'll max out in, like in a regular manual transmission.

Kaumajet

If you find yourself attempting to squeeze that last meter-per-second-squared of acceleration with the paddle shifters, you may want to reconsider choosing a 5500-lb luxury SUV.

scottybdiving

I would think they could be used for down shifting on steep grades or while towing to use the engine for braking.