I have a 2014 GL350. On three different occasions, the transmission malfunctioned by holding an inappropriate gear. The specifics are as follows. First, on each occassion the trans was fully warmed and I was driving on flat and level roads with an unloaded car (ie, light load conditions). This all sounds more like a software problem than a mechanical issue with the trans. Does anyone have an ideas?

After the first incident, I took the car to the dealer and got the standard "Could not replicate" line. I'm scheduled to take the car back in next week, although with the problem being intermittent I don't hold out much hope the problem will present itself when the tech drives the car.

 

I haven't seen anything like this on my 2013, but tend to agree it seems like a software problem. I did check my shifting on the way home tonight, it varied when it shifted between low 2K RPM and 3000 RPM, but always shifted. Going around 60mph I was in 7th gear, at least I think I was. Pushing the up paddle kept it in D, pushing the down paddle put it in D6 and the tach rose a bit.

 

My 2013 GL350 under the best conditions shifts at 1850-1900 rpm, I did notice one time last week that it was holding the gear at about 2500 rpm and you had to press the pedal down quite a bit for it too upshift.

 

Dog, I agree this may be software but also could be a fault with the trans module. If Im correct, the trans will default to 6th gear only when it goes into limp mode if it recognizes a fault. This sounds like what is happening due to the fact that the paddles were also inop. I assume the dealer has scanned for codes already

 

For demonstrating the problem consider getting a dashcam or using your smartphone as one. I use my phone as one - just mount to windshield and run software (I use one called VideoReg for Android). When the problem happens, grab the phone/camera with one hand and record the problem and save the video. Then play back the saved video for your service advisor. If you don't want to fiddle with the phone while driving then just mount it somewhere so it's pointed at your gauges.

 

Not sure what the problem is with your GL but it sounds like the issues I had when my turbine speed sensor went out on my GL450's transmission. It was covered under warranty but doesn't usually occur until you get higher mileage.

 

Well, frankly you need a clearer relationship with the service dept at your dealer - it is standard procedure with the symptoms you describe to do Star log diagnosis and full reporgram of the tranny software - that takes about 1 1/2 hrs shop time - reprogramming is like 40 minutes on the system... all that is what I term "Mercedes cloud" - hooked up, cloud reads, cloud reprograms... does tie down a tech and console - but he can do other mechanical stuff on other rigs while it is getting done...

 

You have to connect the SDS and the actual programming part of the trans module takes less than 10 minutes. They will read out adaptation for each gear and see if anything is close to or out of spec. If they determine an adaptation is needed, they will take the SDS on the road and "adapt" the trans. The adaptation is the longest part

 

Blown V8, yes that is what I meant by saying it goes into limp mode with the speed sensor. 99% of the time though you will get a check engine light or a code in the trans module for this

 

I'll see if that's the dealer's plan. Thanks.

I'm curious as to what you mean "...you need a clearer relationship with the service department...." I have a problem with my MB. I take the car to my local MB dealer, describe the problem and ask 'em to fix it. They tell me they can't replicate the problem so they can't fix it. When the problem happens again, I take the car back. I haven't pissed them off (that I know of), so what else am I supposed to do?

 

Let me be clear - with the condition/issues you described - under Mercedes procedure your truck goes for full tranny diagnostic/reprogram of the electronic tranny control system - nonsensical dealer comment "cannot replicate the problem" - this is now, not some '90's mechanical tranny - they blew you off, their ignorance or their intention, doesn't really matter...

I would suggest you tell them you will call Mercedes Customer Service and file a service complaint if they don't address your issue with full attention - and believe me, they do not want that demerit from MB Customer Service on their CSI.

 

So far, they told me to bring it in again and they'll "check the car/software/transmission top to bottom and see what's going on." I asked specifically if they plan to do the Star log thing and reload the trans software, but I haven't heard back on that yet.

Your comment about the dealer not wanting the demerit, reminds me of another situation I ran into with the selling dealer (who is not the dealer that is involved with the trans). I had a poor experience with my salesman and he knew I was unhappy. It got so bad that he had another salesman handle the delivery.

After I took delivery, I waited about two months for the MB survey that I figured was sent to all new owners. When it didn't arrive, I called MB customer service who told me that they E-mailed the survey to an E-mail address that I didn't recognize. It wasn't just a typo in my address, it was a completely different address from mine even though MB has my correct E-mail (the customer service rep told me the E-mail address they have for me and it was correct).

No matter, I said, just send me another one. The MB reply was that it's impossible for them to generate another survey and send it to me! I refused to believe that and asked for a supervisor. I went through multiple layers of supervisors and ultimately talked to a fellow in the survey department and all gave me the same line about it being impossible to generate another survey and E-mail it to the correct address.

But wait, there's more. It turns out that the surveys are sent to E-mail addresses furnished by the dealer; specifically, I'd guess, by my salesman. So think about that - the salesman knows he's going to get a bad review, the wrong E-mail is supplied to MB and I therefore don't get a survey in the first instance and can't get one thereafter. Bullet dodged. What a stroke of good fortune for the dealer.

It could be a coincidence, I suppose. But in my opinion...actually, I'm guessing...it isn't too much of a stretch to believe that the salesman intentionally supplied the wrong E-mail knowing that he and dealer would thereby dodge the bullet that is a bad survey.

When I talked to the fellow in the survey dept at MB, he said that although he can't (won't?) send me a survey, he'll take down my comments and pass them along to whoever needs to know. Right. That was not very satisfying.

Anyway, I'm still pretty ticked about the whole thing.

 

I'm with fabbrids1 on this, given your experience, I'd have taken it straight back and left it with them till they fixed it.

If they said they could not reproduce the issue / couldn't read codes in the gearbox I'd want to see the STAR system connected and reading no codes myself.

Knowing a little about how these things work, your gearbox module should/would be littered with faults!

My money is that this thread will end with a new gearbox fitted, keep the news coming!

 

For one, I didn't know about the Star thing at the time I took the car in following the initial occurrence of the problem. Secondly, if they tell you they can't find anything to fix, I'm not sure that telling them to fix it anyway would be productive. Maybe going to another dealer would be a good move, but just telling 'em to fix something they say they can't find doesn't seem like it would go very well.

In any event, now that I have multiple instances of the malfunction and I was paying close enough attention to be very specific on what was going on, not to mention that I specifically inquired about the Star diagnostics, I'm optimistic that they'll do something constructive and resolve the problem.

And I'm hoping it's just a software problem. I really don't want 'em to start tearing things apart if I can avoid it.

 

I'm just hoping your car gets fixed as soon and as simply as possible, but as I say given your description I'd bet a beer you end up with a new gearbox, but happy to be wrong.

 

Most definitely they can't fix what they can't find……..at this point, however, what you are asking them to do is show you the "find process" …..if they have done all that Fab and others have suggested is, in fact, proper diagnostic for the situation, THEN it would true statement that they can't find anything. They should not be reluctant to do this…… I am very fortunate, my service guys would be suggesting this process to me before I would ever have to suggest it to them!

 

I take the car back on 12/10, so we'll see.

 

Good luck - people skills - are key to enjoying luxury in life..

 

As luck would have it, the transmission acted up again the day before I took the car back to my dealer. The trans was holding a lower gear than normal for the speed being driven, the paddles failed to function and upshifts were harsh and occurring at much higher revs than normal. And I took video while it was occurring. As before, once I cycled the ignition, the trans worked normally.

Anyway, the "Team Leader," who I understand to be a supervisor in the tech department, and the service adviser watched the video. The Team Leader then agreed that the there was a problem at least insofar as the non-functioning paddles are concerned. He still wasn't necessarily on board with the trans failing to shift into an appropriately high gear or with the trans shifting too harshly and at too high an RPM because because the video didn't show the load conditions I claimed were present (moderate acceleration on level, paved road). That kind of annoyed me, but even if they only believe the non-functioning paddles, my guess is that everything else will be fixed once they fix the paddles.

Their diagnostics failed to show any fault code and there are no software updates for the transmission. The Team Leader said that it is impossible for him to simply re-load the software related to the transmission in the absence of an MB software update.

The next step is to bring the car back after the new year and leave it for a few days. The Team Leader will contact MB to see if they have any ideas.

Meanwhile, I'm hoping that the problem re-occurs. I'll take more video, including some to show that the road is level. That, combined with a view of the tach and speedo as I accelerate should be the proof they need of the transmission shifting at too high revs and holding a lower gear than it should at a steady speed and under light load.

 

With home phone # and VIN# in hand - call MB Customer Assistance (800) 367-6372 - start with Option 4 - then I believe Option 4 - and tell Customer Service on two recent occasions - including one with Video - that you have specific transmission problems and that your dealer did not address and correct.

best to call in the morning - Mon-Fri based on East Coast time zone.

Keep the beat !

 

Thanks for the suggestion, but the dealer seems like they really want to fix the problem. I'm not getting blown off, although I was more than a bit taken aback by the suggestion the video didn't show the load conditions so they aren't yet willing to accept my claim of shifting at too high revs and failing to upshift when it should. In any event, I think I'll let them continue their efforts for at least a while longer before complaining to MB Customer Assistance. Their next step is for them to call MB, anyway, so it looks like my problem will get to there via a much more friendly route than if I call MB to complain. Maybe the time to call MB to complain will come, but I don't think that time is now.

Regardless, the dealer tells me that MB is on a shortened holiday schedule until after the new year so waiting until then is best anyway. And if I have another episode and get more video, that will be a real plus.

Oh, I forgot to say in my post #19 that during the most recent transmission episode the trans wouldn't kick down any gears when the throttle was suddenly mashed to the floor (as if to pass). That same problem also occurred during prior episodes. That issue was pretty apparent on the video because I said on the video "I'm now mashing the throttle and the trans won't downshift" and you can see on the video that the revs go up a couple of hundred (due to the torque converter), but no downshift occurs.

 

I think you are being very reasonable.....but I would be moving to Fab's suggestion fairly soon if this is not resolved shortly as it begins to sound like an "unsafe to drive" situation.

 

The problem still exists. Dealer is stumped. My service advisor says they called MB factory techs who had no idea what's wrong and factory boys offered no solution except to "tell the customer to bring it back to the dealer while it's malfunctioning."

BTW, dealer didn't know what the "Star log diagnosis" mentioned by Fab was. Said they assume it meant to do the standard scan, which they did before this visit and again at this visit but nothing shows up.

This sure seems like a software problem to me, but the dealer says they can't just delete the trans software that's in there and then reload it. They could update it if there were updates (there aren't), but they can't just dump what's in there and then re-load it. Supposedly, that's impossible. I asked why it's impossible, given that it's just a computer, and was told nothing more than "because it is."

It seems to me that software can be deleted/re-loaded at will. I asked to have someone at MB factory call me to explain why the software can't be reloaded. The SA said he'd see what he can do to make that happen.

The problems described in my prior posts occurred 4 times since about October, but haven't occurred for 6 weeks or so. Truth-be-told, I'm fine with just driving the car until the problem occurs again and then bringing it into the dealer while the malfunction is in progress. (On the other hand, I suppose there are scenarios where a malfunction of the type involved here could be dangerous so maybe i need to re-think whether I'm really okay with just driving the car until the problem crops up again.) Anyway, what I'm not so agreeable with is that the trans doesn't shift very smoothly and I think that issue is related to whatever is causing the bigger malfunctions described in earlier posts.

I think the less than smooth shifting will be fixed once the other malfunctions are fixed. But I must put up with the shifting pending them figuring out the cause of the other issues because the the dealer says the trans shifts just fine and there's nothing they can do about it. So that leaves me driving around waiting for the obvious malfunction to occur while all-the-while being very annoyed by the somewhat harsh shifting.

I told the SA that I want to drive one of their inventory '13 or '14 GL350s (either new or used) back to back with my car to prove that there either is or isn't the shifting issue I describe. The SA says he's glad to do that, but they have no GL350 inventory. He says he'll call me when they get one or, perhaps, he says one of his GL customers may give consent to use their GL for comparison.

I traded in my Toyota 4Runner, which I liked, on the GL because I wanted a smoother, more plush ride. Well, although my GL's ride is much better than my old 4Runner, the trans on the 4Runner was smoother and that's just nuts.

The SA is a nice fellow and he seems to be trying to help. No issues there and that's good, of course, as well as much appreciated. But, the problem isn't getting fixed and I'm getting more annoyed by the minute.

 

we had similar issues on our 2007 GL. first time they replaced couple of solenoids in transmission, second time they found a servo in the air intake that was getting stuck so engine was starving and the car computer system responded by not allowing to shift. Our service tech said there is also a electronic card in transmission that can cause similar issues. Fortunately for us all this happened when we still had extended warranty. Hope this helps

 

Thanks for the input. Not sure your situation is applicable to the current gen GL, though.

When I posted my last response, I hadn't yet picked my car up from the dealer. When I did, I saw that just under 200 miles had been put on it during the 3 days they had it. I was told that MB wanted them to drive the car that much to see if the problems re-occurred.

The dealer knew that the trans problem last occurred the day before I last brought the car to the dealer back in December, which was 1200 miles before this visit, and hasn't occurred since. So, while anything was possible, the chances of the problem happening in the next 200 miles were pretty slim...the point being that driving the car for 200 miles waiting for the problem to occur was a pretty useless act and the outcome (no re-occurrence of the problem) all but a certainty. On the other hand, the problem will re-occur sometime and I guess it was as likely during those 200 miles as any other.

I'm not annoyed with the dealer because MB told 'em to do it, but I have to figure that the dealer told MB the chronology and MB wanted the miles put on the car despite that. Anyway, the dealer filled the fuel tank before returning the car to me. I'm not sure what the fuel level was when I dropped the car off but it was a nice gesture in any event.

What's really starting to get to me is that they have the malfunction on video and still won't do anything. Once I get another episode on video, I plan to be, shall we say, a bit more insistent that they do something. I'm not sure exactly how I'll do that but I'll think of something.