Andyjacob

When i am driving slow and put slight pressure on accelerator - car will pulsate/stutter for about 3 seconds before returning to normal. Feels like a jerking. Was worse on going up a hill but now happens occasionally on flat roads also. No noise at all - but you can feel it. I have read threads that say torque converter, try Tran oil change, fuel pump, plugs; my mounts do look bad - could that cause it? Trying to not blow a fortune on this- hoping someone may have fixed this and can comment on their solution.

chassis

What condition is this car? Sounds challenged from your description.

How many miles?
When was the last oil change?
When was he last transmission fluid change?
When was the last spark plug change?

Does the shudder happen at highway speed when you tip in and out of the gas pedal?

Andyjacob

110000 miles, oil change just done, transmission oil serviced at 50k, original spark plugs, doesn’t happen at highway speeds ever

pjhiggins

2011 GL350 does the same thing in 2nd/3rd gear. Low rpm shudder that used to only happen on slight grades, now happens on flats, especially in traffic situations. Interested to hear everyone’s thoughts.

119K miles, trans fluid done at 91K, original plugs, oil every 6000K.

eric_in_sd

You guys need to hook up a diagnostic computer and find out what the ECU is telling you. Not just an OBD scanner; while that would be a start, you need to find out what information the ECU is reporting when this happens.

Otherwise you are lost. Even with a good computer it is like calling to get directions to a house party and a drunk chick answers the phone.

Elbeau

While I think the "drunk chick" is a bit of an exaggeration, your point is valid. I have that low speed shudder and my MB specific OBD scanner has nothing to say about it. However, the OBD scanner does have the ability report a number of transmission related codes. Obviously, though, the absence of a reported fault doesn't mean everything is okay.

I'm bringing my GL450 in to the mechanic next week and I will report back what is found.

Andyjacob

Let us know what you find out. My mechanic thinks it is coming from engine and transmission mounts (which are original and likely bad); I am not convinced. It seems to happen as I accelerate and as trans is trying to shift. Perhaps the mount is keeping transmission in place as it is attempting to shift and absorbs the stutter in normal conditions..

Elbeau

Yeah, I'll update when I know. It feels more internal to me. My passengers don't notice anything, but I feel it. It's more like an uneven response to my accelerator input. I think a mount issue would be transmitted to the body.

gb25

FWIW, I changed the motor mounts and transmission mount on my 08 gl320 and the slight shudder that I had went away. I didn't even know that it was there til I drove it after changing and it was a lot smoother. I guess I got used to it. I only changed them because I got them cheap and knew they were prone to go bad.

If your trans mount is original, I'd probably start there. It's not too expensive and pretty easy to change. BTW, none of my mounts looked bad at all and they all weighed the exact same as the new ones.

Elbeau

Well, I'm bringing it in next week and will find out. I'm pretty sure it needs a fluid change anyway. It's right around the second change mark.

Andyjacob

Thanks for the input - I haven't been able to find a good video on changing transmission mount. Does car have to be on 4 stands?

gb25

I wouldn't think so, as long as you can get underneath it. Two bolts to the crossmember, then four bolts to the transmission.

One thing to look out for is my old mount had two threaded studs with nuts for the crossmember. The new one that I bought had threaded holes. So I had to buy bolts for it.

I put a jack underneath the transmission (or transfer case.. don't remember) to hold it up, then removed 6, 7, and 8 in the attached pdf.

eric_in_sd

Post back when you get this done. I sometimes get a clunk pulling away from a stop, and am wondering if it is the transmission and/or motor mounts, and am curious what effect it has for you.

Max Blast

I have the same clunk from a dead stop, but that is my stretched chain in my two speed transfer case… At least that’s what I think but it could also be cracked or worn giubi or a transmission mount.

eric_in_sd

It is just a guess, but it feels to me more like the whole motor shifting sideways than slack in the drivetrain. This I say because it is not consistent and is deep and solid sounding.

Ducatimark

So what was the result? This is exactly the problem I'm having with my 2011 GL450. Any help appreciated!

KWStan

In my case it was the transfer case - the chain was stretched & skipping. Exact same symptoms as described. Replaced T/C with a low-mileage used unit & problem solved.