On the 4th day of my 2014 ML 350BTC ownership I was going slightly downhill, barely touching the accelerator to keep the speed at about 25mph when the car started bucking like a donkey for a few seconds. Since then I noticed a few times at low speed/low rpms that the car either buckled a little or it felt like a gasser not getting sparks on all cylinders. In all cases it happened when the engine had already warmed up. That doesn't match at all with the silky smooth ride I've experienced otherwise with this car. Is this normal during break-in period? I saw a few threads mostly from 2012 where other people had experienced similar issues but I would expect that by now MB has fixed these issues, right?

 

You may have just found a unique condition that makes the transmission hunt between two gears (very light load on the driveline due to the downhill coast coupled with light throttle application making it think an up shift is appropriate, but the next higher gear lugs the motor and triggers a downshift). This transmission had a lot of odd bumpy shift characteristics when it was first introduced. It's greatly improved since then.

I've had my 2014 BTC about two weeks and have noticed an odd (firm) shift every now and then under very light throttle application at low speed (like when in traffic and I start to accelerate again as the transmission is in the middle of a downshift). but I'm not worried about it.

 

Mine has done it, too on occasion. One time it down shifted so hard and with a bang that my daughter thought we had hit something.

It's really a shame that MB could not have properly fixed this transmission after 7+ years in service.

 

Only owned my 2014 ML350BT for months and never experienced anything like you are describing.

My transmission does feel a little like it is slipping upon shifting at the beginning of the day but after reading about others with the exact same problem, I feel it is normal but will question the dealer at my 10K.

I have on a few occasions had the transmission shift a little rough when it goes from slowing down to re-accelerating. Can't blame the transmission as it can not read my mind.

Other than that the tranny and motor package has been silky smooooth.

 

I'm not talking about the transmission shifting rough, what I'm talking about is caused by the engine

 

I would suggest you explore the use of the paddles - there are two "actions" to explore for both acceleration and deceleration situations - especially with BT.

1-sec pull left/right ****s down/up one gear respectively - now, with a 7-speed transmission 1 gear may or may not be a significant difference

3-sec pull left/right - left brings you down to "power" gear for that speed - again for either acceleration or deceleration - right 3-sec takes you back up to auto.

I would suspect this is your 1st diesel - and you have the best ever - explore to adapt your driving habits - there is a lot of enjoyment you will unlock over the next few weeks !

 

How should my driving habits be when I'm just going with the flow driving in the city from traffic light to traffic light? I drove a Jetta TDI with stick shift for a while when I was still living in Germany. Never had any bucking issues with the Jetta. The only car with bucking issue I can remember was the W124 where the rubbery connection between rear differential and the part going to the gear box (cardan shaft?) was faulty. Mercedes replaced them under warranty/recall.

 

I dropped my ML off on Thursday morning and the technician was able to reproduce the issue. When driving slowly at a steady speed or slowly accelerating it feels like there were bumps in the road when there aren't and sometimes the rpm-needle jumps a little up and down.
On Thursday afternoon they told me that they want to keep the car over night just to make sure it's fine. On Friday afternoon they told me that the car needs a software update which would be done remotely from Germany but the Germans wouldn't work on weekends, so it has to be done on Monday. On Monday they called and said the car was ready. When I picked it up they told me that the transmission fluid was low and they topped it off but the software was up to date. So I'm still driving with a bucking and jerking $60K car that has 640 miles on it which I had waited for for 3 months. The service dep. guy told me to drive for another week because the car is new and has to learn. My ML has had that issue for the last 500 miles and I really doubt that it's going away just by driving. They also told me that they can't replace any parts because there is no error code in the computer. I have to say, this really sucks the fun out of getting a new car.

 

A user on this forum, Katiesdad7, successfully lemon lawed his ML 350 for the bucking you are experiencing. Search the forum for his posts.

 

Yep if they can't fix it read the lemon law booklet that came with you vehicle and follow the rules to the letter. MB will notice and take you seriously. I have had a friend who used the lemon law and it worked perfectly.

 

Lemon Laws vary by state; but once you start the process, you will most definitely get MBUSA's attention.

 

You might want to buck (sorry couldn't resist) this up to MBUSA before going Lemon Law. It seems that it takes a bit of nagging, but once MBUSA opens a case on it, it should get taken care of. With more than one of this thread stating they have had the same problem, it's obviously something they know about.

 

If I had to I would look into the lemon law but I'd rather have my car fixed. I don't think that I can get another custom ordered ML350BTC and I certainly wouldn't accept an ML250 as a replacement.
I went back to the dealer this morning and the service manager drove it for a few minutes. He experienced it as well and he said that he'd never experienced that before. He also said that they would open a case with Mercedes and we made a new appointment for me to drop off the car.

One other thing I noticed today... when I push the accelerator from a stand or slow speed hard enough that the car bounces back, there is a noise as if something was loose. I hear it in sport and comfort mode but when I set the airmatic to raised level, I don't hear it. Is that normal?

 

I agree and would want my vehicle fixed, too!

But just in case, I would read the booklet.

Hope they get to the bottom of it soon.

 

The BT should not be bucking. Paddles are not the fix and shouldn't be.

 

I got my ML back after 5 days with a fresh programmed transmission and torque converter. I didn't even know that torque converters have electronics. One day later (today) it bucked again and the check engine light came on...back in the shop. I'll have to pick up my parents at the airport tomorrow with a loaner car... so much for the surprise pickup with a new car that I had planned.

 

This is sad as it shows that MB has no idea what is going on.

You may have no choice but to use the Lemon Laws.

 

I took delivery of my 2014 ML350BTC 5 weeks ago and as of now it has spent more time in the shop than in my garage due to a bucking issue. Thinking that an airmatic equipped, fuel efficient bluetec would be perfect for a road trip, I planned to drive with my parents (visiting from Germany) to drive from Chicago to Denver and back.
Last time I saw my ML was on 8/7, so I called the dealership on 8/14 asking if my car was fixed and if not, it it's ok to take the loaner car to Denver. The dealer told me that loaner cars can't leave the state and they would get me an enterprise car for my trip, so we ended up driving those 2000+ miles with a Jeep Grand Cherokee The Jeep is not bad but it's not a Mercedes either.
When I returned the Jeep today to get back into another loaner car I was told that a Mercedes Engineer had personally checked out my car today and they replaced two temperature sensors and the exhaust. I was told that the check engine light is off now but my ML is still bucking. Now they are going to put different fuel in the tank to see if that's causing the issue which would surprise me because my ML has never seen anything but D2 highway diesel unless my local gas station is lying to me.
The day I picked up the Jeep, the service manager from my dealership told me that he complained to Mercedes and they were ready to get me into another car. I asked if they could really get me another (discontinued for the US) ML350BTC and he was told yes they could. Today I asked about that option again since I'm starting to lose trust in my car and he said that they wanted to fix my car first and then talk with me about that or other options. He also said the other day that they would probably take over some payments to make me happy. So... once they fix my ML (positively thinking, lol) are they going to offer me a couple thousand dollars so I keep it instead of pushing for lemon law replacement?

 

If they don't make it 100%, don't accept anything less!

 

You have more patience than me. I would not have the time to let them mess with my vehical multiple times with no resolution in site. I would have Lemon Lawed it the second time it bucked. At this point there is little they could do to restore the trust I need in my transportation!

 

I got my ML back yesterday, this time it spent 2,5 weeks in the shop, the first two times 5 days each. They "think" that the bucking was caused by the diesel which I still can't believe, at least our A6 TDI doesn't have issues with it. They sent the diesel to a lab to have it checked. On the bright side it didn't buck since I got it back yesterday. The noise during bouncing when accelerating was caused by a heat shield they said. It's nice after 4 weeks of driving loaner and rental cars, to finally drive the car I ordered back in April but I can't enjoy it. Maybe I'm overly dramatic but right now I just feel sick to my stomach. I'm supposed to get a call from MBUSA today.

 

That's just awful. The worst part is that you can't get another 350BT.
Unless you do a national search and find one that's loaded and offer MBUSA to make a switch.

Good luck, I hope you get some satisfaction.

 

Thanks! I got that call and as expected, they can't get me another 2014 ML350BTC. They offered a compensation as alternative which I've accepted.
I don't think any other brand would have done that, so assuming the issue won't come back I'm done complaining.

 

The fuel was the first thing that came to my mind when I was reading about your unfortunate experience. It had been my understanding that the diesel fuel in Illinois has too much bio content for the new generation of passenger diesel vehicles. I had heard rumors about the dealers in Illinois making buyers sign something about this; is it true?

 

No I didn't have to sign anything about the fuel I'm getting. They actually gave me a flyer stating that Mercedes Diesel vehicle can be driven with B5 - B20 but it shouldn't be if possible. My gas station has a sticker on the pump indicating that there is no bio in it and they confirmed that when I asked. From what I've read online, you might get issues with diesel that contains bio in the long run but I didn't see anything about a brand new car bucking after 3 days of use.