sll914

We recently purchased a low mileage 2011 GL550 and are loving it. One thing we noticed however is that there is significant lateral motion (side to side rocking) when travelling over bumps or uneven roads. Its alot more noticable in comfort mode and less noticeable in sport mode. I've no problem with feeling the bumps in the road (i usually keep it in sport mode myself) but its al little unsettling when these bumps produce the side to side motion...

So does anyone else notice this in their GL? Is it just a result of a heavy SUV with a high center of gravity? Maybe a swaybar problem or bad shock on one corner?

georgeore

I have the same issue with a 2010 GL450. Interested to see if this is normal or an issue that needs attention.

will_w204

While there can be suspension issues with the vehicles, and most certainly will be with mileage and age, the absolute first thing you want to check is alignment. They will rock like this (normal), but it is more pronounced when alignment is out. Of course, I'd expect it to rock more in comfort than in sport.

Also, I'd run minimum 34psi cold, all around.

sak335

This is normal. You're driving a vehicle with a high center of gravity. In comfort mode, the air shocks have less pressure and allow more rocking to occur over road surface undulations. Sport mode increases the pressure in the air shocks and allows less movement (distance) but I would think it would also produce more smaller motions. The only cure is to drive a car instead of an SUV. If you want to convince yourself, use the airmatic to raise the suspension to maximum height, then drive down a road where you notice the rocking occurs. Then, lower the vehicle back down and drive the same road. You'll notice that it's worse when the suspension is raised up.


This is physics at work; the weight of the vehicle acts as a lever over a greater distance and all the suspension wizardry in the world is going to struggle to contain it.


An alignment is going to do nothing to cure this. Unless you have had suspension work done (tie rods, control arms, etc.) there is no reason your alignment would be out of spec. Alignments are probably the #1 most over-sold automotive repair ever.

alx

It is called "head toss".

Welcome to the club

2010GL550

I agree that's it is probably normal. Make sure your tire pressures are set correctly. That might have a small effect on it too. I usually run my tires at the max recommended pressure (per the inside label on the fuel door).

will_w204

While the general behavior is normal, I had mine in the shop because it was dipping and bobbing absolutely more than usual, they replaced steering knuckles, which needed to be done, but what finally resolved it was an alignment. So, depending on what the OP's seat of the pants is telling him, if it's always exactly like this, or if it's gotten more pronounced than before, an alignment absolutely could fix it.

Also, understand that the dealer didn't "sell" me an alignment, they didn't even ASK if it had been done recently, nor did they suggest it. I take all my cars to my guy at the Ford Quicklane, where I can get a 4 wheel alignment for $65. It was my last-ditch effort to get the damn thing driving correctly after spending 2 weeks in the shop.

So, yes, in this case, a 4 wheel alignment firmed up the motions in the vehicle, returning to a "normal" rocking, from what had become a flaccid, "wallowing" rocking. So, sorry to burst your bubble, but an alignment absolutely can fix oddball tracking and handling behaviors, and especially considering your description of the vehicular dynamics of a tall, heavy SUV, logic would say (and has taught me) that misalignment in this chassis, based on me getting 3 alignments in 18k of ownership, all of my own free will based on a hunch, can cause issues that are more easily felt that in say, a C350 sport

My primary theory has to do with camber, which you can visibly observe is pretty extreme on these vehicles when in spec. If camber is off in the front, meaning the wheel is more perpendicular to the road, as in more negative camber that spec on one side, logic would dictate that the vehicle is more liekly to "dance out" over that wheel if that wheel encounters a low-spot on the shoulder, or a dip, and that is exactly what I felt on the right side. It was very, very pronounced.

If OP believes there is a problem in the way the vehicle handles, either in cornering, or straight-line handling of uneven surfaces, and the vehicle is out of warranty, the choices are:

1) live with it because at least some of it may be normal
2) Get an alignment for $60-$100
3) Get new tires for $800-$1200
4) Start throwing thousands and thousands of dollars at various suspension parts, such as $1000 struts, $500 steering knuckles, etc

I'd start with #2

srfrboy

I have the same thing occurring on my 2011 GL550. Only 45k miles on it. My local dealer told me that it is completely normal.

sll914

OK, thought I'd post a follow up. We took it in to the dealer and they replaced a defective front shock assembly. Picked it up and guess what, it drove just the same. We decided to just live with it and move on.

Well, it kind of needed new tires but I was delaying to make sure we got all they were good for considering the expense of the new set. We ended up putting some new Pzeros on it and low and behold, the wonky handling over bumps is gone!! All I can assume is that there was some kind of uneven tire wear issue that was causing it to happen.

Before you say it was an alignment job that went with the new tires that actually fixed it, I have to say that a full alignment was performed at the dealer when the shock was replaced with no improvement at all. Also, the new tires were mounted and balanced without touching the alignment...

Not sure I have any concrete recommendation to others regarding this issue but if you're near needing new tires and having this problem, go ahead and do the new tires if other remedies haven't fixed the problem.

-- Happy GL550 owner again...

CBR2200

You're happy until your PZero's wear out in one year.