I recently inherited a 2012 gl450. I really like the car and I unfortunately have an emotional attachment to it. Unfortunately it has developed a shudder during low rpms during acceleration and usually when going up a hill. This only seems to happen once the car has warmed up.

When I picked it up in PA I thought I felt a little shudder after a 2-3 shift so I took it to a transmission shop and they told me the fluid level and quality looked good and the trans was fine. So I drove it to AZ trailering a 19ft camper. Every once in a while it would shudder but it didn’t get bad until the last 100 mi. Limped it home.

I kept driving it and the shuddering seemed to be more frequent but still random. My code reader did not show anything so I took it to a local shop and there was one main error code that popped up. It was the sensor on the tumble flaps. Sure enough that little plastic pivot was broken. It seemed like the tumble flaps being in random positions might cause the random shuddering so I decided to replace the whole manifold.

I ordered a cheap version of the intake manifold (not sure if I’m gonna regret that) from eBay and I replaced the old one. While I was fixing that I noticed more oil than I would have expected in the intake manifold. I checked the Pcv valve and it was basically gone. Replaced it with a new one. I also replaced the air filters, cleaned the fuel injectors, and replaced the spark plugs while I had all of this apart.

I put it all back together and it seemed like I fixed it for about a week. So I sold my old car. The next day the shuddering was back. Damn it.

I am still driving the car but a little confused on what to tackle next. I hooked up a nicer code reader to it (icon t7) and I have no active codes. The only thing I can see is that the evap pressure is way out of spec.

Right now I am leaning towards the transmission or torque convert being the problem because I have had a few random clunky shifts. Any ideas would be greatly appreciated. Thanks.

 

The shuttering had nothing to do with your intake manifold so I hope you did that job right and didn’t cause any foreign object damage to the internals of the engine.

This is either as simple as a cracked giubo in the driveline, or your torque converter going out or locking up when not commanded to

I recommend getting under the car and looking for a cracked rubber disc that connects each driveshaft. These are known as giubos.

 

Although all your exchanged parts could be considered like maintenance there no logic to spend more based on a Fault Code without a step by step diagnosis.

In any decent workshop, starting from any fault code a Diagnosis Routine need to be started, based on experience if the technician is trained or by simply pressing the 'Continue/Test" button on the Xentry Diag System.

This way, the Evap system will start to play by himself, the tumble flap as well...and so on. Plain English, nothing complicated. Sure, a lot of folklore or blame for MB models...

Reading a fault code, is not diagnosis.

 

I’ll check out those joints. That seems like it may fit the symptoms. Most of the other stuff I did seemed like a long shot but probably needed to be done for maintenance anyway.

 

I checked the giubo joints and they all looked good. I didn’t see any cracks or threads coming out of them. I did see some oil leakage on the transfer case. Should the transfer case be able to move upwards from the bracket that is below it? I was able to move a transfer case up about 4 to 6 mm from the bracket below it with my hands.



So at this point, I’m guessing that I need to troubleshoot the torque converter. Are there any diagnostics that I can do myself or do I just need to take it to the dealership to get checked out?

 

No, the transfer case should not move perceptibly.
While you are in there, check for other things that are visually not correct - perhaps a torn or collapsed motor mount/transmission mount.

converter is checked a interrogation of the TCM using DAS/Xentry. Any reputable independent mechanic, or - God forbid- the dealer will have this.

 

You are reinforcing my fear of a dealership. I’ve never taken a car there before but these Mercedes are more complex than the vehicles that I have worked on in the past.

 

they are really not. Access is pretty good compared to most other cars. I’ve worked on lately.
The only way to own one of these is viciously DIY everything and get a code reader that speaks Mercedes.

 

Will an icon t7 speak Mercedes. A friend let me borrow that code reader. Or is another type required?

 

I have no idea what that is but there’s only one way to find out. You need something that has by directional capability that won’t just spit out P codes.

 

The icon t7 is a harbor freight code reader but it does say it’s bidirectional.

I just checked it out further and it does not do any xentry diagnostics. Do you have a setup that can do this? Do you have one you can recommend or is this something I’m going to have to rely on a shop for?

 

For beginners, iCarsoft 3.0 for Benz or Launch Crader Elite are both under$200 in Amazon.
From your first message, mentioned that a transmission shop said level and quality of the fluid is good, is this a MB specialist or a general transmission shop.
I still believe there are 2 possibilities for your issue, one of them is a more mechanical issue like Transmission mount or engine mounts, driveshaft, axles or differentials OR level or quality of the fluid is off. Dirty fluid cause all weird stuff.

 

I only recommend xentry clone systems.
Lots of information on the board here about which version.

but back to what others are saying, this is a mechanical issue that you need to eliminate first before going down the code reader rabbit hole.

 

Here is the video (see link below) of me pushing on the transfer case with my hands. Is this movement normal. I wasn’t sure if it is supposed to be hard mounted to the bracket below it. There is relative motion between the bracket and the transfer case.

https://share.icloud.com/photos/051d...JTxtjHFs4rCBwA

 

sounds like leaking or fluid-empty motor mounts to my 2011 E350 Estate experience, so get your VERY qualified independent MB Mechanic to check the 2 motor mounts & the rubber transmission mount. The right motor mount is very difficult to reach, & my top-rated Indy MB mechanic
told me that the engine has to be lifted OUT of
vehicle to gain access to right mount!
Used to be, in the 124 & 210 E Series, all mounts
were inexpensive rubber. The 212 Series has the 2 oil filled motor mounts which will leak over time.
My San Francisco mechanic quoted over $2000
FOUR years ago to replace 3 mounts!

 

Are the motor mounts active motor mounts? I had those on my Honda pilot. I was not a fan. The mount that I showed on the video was the transfer case. Were you suspecting the motor mounts based on the symptoms that I originally posted ( ie. shuddering)?

 

if you’re talking about a E class Mercedes, a lot of the parts and procedures are not comparable to an X164 which has a lot more space and access.

For instance, to do the rear airbags in a E320/E 500 you need to remove the entire subframe. that is not the case in the next 164 -it’s a 15 minute job.

 

you seem to be very adapted getting under the car so get under there with a crowbar and attempt to pry. Failed or failing motor mounts will manifest themselves in the engine, moving around when placed under load such as when shifting from neutral to drive or reverse.. You will see the engine move and it will feel rough across the entire spectrum.

I looked at your video. It’s too short and it does not conclusively show at that mount is bad.
So get under there with a prybar and attempt to force it up and down, taking care not the damage the mount any further

The motor mounts in the X164 are not active. Although previous poster meant well, commenting about other Mercedes parts and procedures to a relative newbie such as you is more confusing than helpful.

 

I won’t be able to check it out for a few days because I just had surgery but the motor mount theory did remind me that I do here a loose clunky sound from the front right of the car when I go over certain bumps at low speed. Sound reminds me of when I’ve had bad antisway bar links in other cars. I did do a quick check of the sway bar link in this car but did not feel any perceptible play. I’ll try to take better videos when I do get time to pry around in there.

Just curious, if it’s not one of the motor mounts or giubo joints and it is something with the torque converter, how would I have to troubleshoot that. Just replace the torque converter, or is there something I can check or test with the xentry system(if I can get access to it?

also, thanks for all of your help. Really appreciate it.

 

Even in your diminished state, you can pop the hood open and put the car in drive/reverse and see how much the engine moves. It should not be much.

there are some values you can search in centry that will tell you how much slippage occurs in the torque converter.

But any other culprit than motor mounts is gonna be a drivetrain out replacement of said components. so let’s not concentrate on that before you rule out all other mechanical bits.

 

I finally felt good enough to check those few things out:

1. Took a video of the engine movement when shifting from park-drive-reverse. It looked minimal to me. I also looked at the motor mount on the passenger side. Looked good to me. Here is a video of the engine movement. https://share.icloud.com/photos/031u...UHZN2_hVWXR6Ig

2. Looked around at all the joints on the front end. The lower A arm mount on the passenger side is cracked. Doesn’t seem like this would cause my shuddering but I guess it’s just something I’ll have to deal with later. I added an image of this below.

3. Took a better video of the up and down play in the transfer case mount. I only had to apply very little pressure with the crow bar to get movement. It looks like this is some type of rubber mount so I guess movement is ok but it does seem a little loose. Here is a better video than last time. https://share.icloud.com/photos/019M...oTMjzbCU2IRLxA

I did go back and reread all of the input from people on this forum. One of the questions was if I took it to a reputable trans shop when they said the fluid looked good and the level was good. This shop was who my parents used in Pennsylvania but they were not a Mercedes specific shop. Personally I did not really trust them. It just got me thinking. I have no idea if or when this trans has been serviced. Would a transmission flush be a good idea before I go further? If so, is there a good video or thread on this process. I’ve never done it on this vehicle and the lack of dipstick is mind boggling.

 

Definitely not a flush but a fluid, filter&gasket exchange, if you do it yourself, would set you back about $250 for the material, fairly easy job because of the clearance under the vehicle, its basically straight wrenching, except the transmission fluid temperature measurement would be more accurate if done with a scanner, seen some people using laser pointer gun but that was a good method when dealing with 722.6 5 speed transmission.
I`ve done numerous times, let me find my pics from my last time.
Actually I found a better link for you, I posted this back then to the other forum lol.
https://www.benzworld.org/threads/x1...hange.3132268/

 

I am 90 percent of the way done with the fluid change. I just need to refill it. I bought the icarsoft scanner that the internet said should pull the trans temp. I also changed the transmount because there was a guy with a YouTube video about his gl550 with a shudder and that was the fix. I don’t think it’s the mount because the amount of motion with the new mount seems the same as the old mount. I’ll let you know if this fixes the problem. I give it a 25% chance but the fluid was pretty dark so it needed to be done anyway. Thanks for checking in.

 

I’ve driven it for a day after the trans fluid change and the trans mount change. No shuddering so far but I’ll only be convinced after I’ve put some longer trips on it.

I ended up draining about 8.5 L of trans fluid (by weight) and I put in 9 L and a little bit less than a L came out. I used the Fuchs brand. I was able to use the icarsoft i980 scanner to read the trans temp. I think it was about $100 on Amazon. It was really hard to find the menu where you can query the temp so don’t give up. I’ll give an update in a week or so. Maybe I fixed it, maybe I didn’t, but this forum helped me a bunch. Thanks.

 

with a slight bit of hesitation I’m gonna call this problem solved. I drove the car down a 6000ft mountain from flagstaff to Phoenix and back again at about 80+ mph and I did not feel any shuddering. There was one moment going up a really steep short hill in town where I might have felt something but it may have been my paranoia.

what I learned.

1. dont trust the transmission shop. They just lied to my face and told me my fluid looked good and the level was right. After changing the fluid, I 100% guarantee they never looked at the fluid.

2. people on this forum are helpful. Thanks

3. Mercedes are designed in a very special way. I’m an engineer so I simultaneously understand some of these design decisions while hating them when they break.