Does anyone have experience yet towing large loads - say in excess of 6000 pounds - with a GLS?
My local dealers have lacked expertise when it comes to towing - one of them said I should come in and take a test drive with my trailer when I asked about active body control and how it interacts with towing - except the only GLS580 they have doesn't have the tow package, and he didn't know anything about trailer brake controller wiring. Amazing towing knowledge at Mercedes dealers remains poor nearly 15 years after the GL.

I've put probably 30,000 miles on my X164 GL 350 towing a large airstream - 28 feet, GWVR about 7,000 pounds - it's a 2011 GL 350. The OM 642 Diesel Motor in the GL 350 is hideously unreliable and expensive to fix, and now that I'm out of extended warranty it's time to move on to a new truck. Other than the problems with the diesel motor, the 2011 GL was a good truck - the diesel motor is just a disaster. I'm likely to build out a 2021 GLS580 for delivery later this year.

I saw the thread here already confirming that the green towing plug exists on the X167 GLS's.
I'm looking for other thoughts / advise on configuring an X167 GLS that will be used for towing large loads, plus the overall towing experience with a GLS580.

Are any of you reinforcing your hitch receiver on the X167 like many of us did on the X164?
For towing, is it correct to avoid the larger 22 and 23-inch wheels now available on the GLS, so you have more rubber/sidewall? So stick with 21" wheels?
Any thoughts on active body control, and whether this is a desirable feature, or a too be avoided feature, for those who will tow?
Are the autonomous driving features all enabled while towing with the X167?
Does the Speed Limit Assist feature understand states like California that have different speed limits for vehicles when towing and not towing?
Is the two-speed transfer case associated with the off-road package reliable or to be avoided or to be preferred, especially for those who want to tow heavy loads?
Does the X167 generally feel like it understands towing / was built for towing any more or less than the X164 did?
Is it necessary to step up to the GLS580 to get sufficient torque and power to tow a large trailer?
Are any of you who tow prior GL owners and can you compare the towing experience and functionality between the two vehicles?

Any other thoughts on configuring an X167 GLS if you intend to tow, or on experiences towing large loads with an X167 GLS?

 

I have a 2020 GLS580 and tow an Airstream 25FB. I had a 2014 ML 350 Bluetec and gave up on it too even though it towed the AS well. The new GLS will also get the hitch reinforcement at Canam RV on July 13. I can't answer all your questions but have some info. You should also check the Airstream website towing forums. The GLS driver assist programs for the most part are disabled when you have a trailer hooked up. I have not added any options to the Canadian Spec.GLS580 except I was forced to order the 22 inch wheels with Summer Only tires. It took 363 days from order placement until I received my new GLS. The 22 inch wheels are not a bad choice as the sidewall height is actually bigger then the 21 inch wheel and tire set up sidewall height. My only complaint is the "Summer only" tires as I need All Season and can't get the correct size. In Cal you likely would not see this as a problem. I re-used my prodigy P2 brake controller and connected the wires to the MB provided wires and I cut off the green plug and wired directly. The difference between the old ML and the new GLS is that the P2 controller doesn't wake up on the GLS unless it is connected to the trailer. The back up camera is nicer as it has a view for hitching. I use a weight distributing hitch and sway control. I don't see how E-ABC would work well with a trailer behind. I don't have the 2 speed transfer case AFAIK it is low speed use only so again I question the benefit for towing. The air- matic system is standard and when a trailer is connected it stays i n "normal" height mode. The speed assist uses cameras to read posted speed limits. The other day I noticed a sign that said 50 unless otherwise posted in the city I was entering and even though the speed limit was 80 the GLS read that and it popped up on my screen as speed limit 50. I went with the V8 for the torque as I did not want to take a step back after the big torque from the OM642 but I will miss the MPG. The EQ boost ads torque but it only lasts a few seconds so that is only helpful in short bursts not on a long grade. If you go on the Airstream forum and check my posts my user name there is TRIPPPIN , there may be more useful info.

 

Thanks for the very helpful post.

I'm now engaged with several Mercedes dealers. What's so interesting is that all of them are saying that they believe the GLS450 has sufficient power and torque to pull a 7,000 pound trailer, and that the GLS580 is a personal choice, not a requirement for towing a large load. The most experienced sales guy - who's been with Mercedes for more than 40 years - actively encouraged me away from the 580, and also discouraged purchasing active body control - saying he thinks it will inevitably fail and is going to be super expensive to fix.

Here is an email response to my written questions from one of the dealers. Kudos to them for doing their homework.

> 20 inch rims or larger for towing?
Smaller wheels with a larger sidewall tire would increase ride comfort. I would recommend smaller wheels if you are towing frequently.>E-ABC or not for towing?
Active body control definitely improves ride comfort. I haven’t drove one with e-active body control yet. I don’t believe it is deactivated when towing.

>What autonomous driving features are disabled when towing?
I test drove a 2020 GLS450 and simulated a trailer attachment. The only 2 driving features that were disabled were blind spot assist and steering assist. Every other feature that this particular model had installed worked as designed.

>Does speed limit assist understand towing?
I was unable to find a nearby road to check if Speed limit assist adjusts to a specific limit with the trailer attached. I don’t think it will reduce the speed automatically. If you have distronic you can adjust the speed limit accordingly.

>Is the two speed transfer case more reliable / heavy duty than the single speed?
I haven’t seen any failures with the transfer case on this particular model.

>How do the X164 and X167 compare when towing? Any big differences?
My assumption is this model is very similar to the 164 chassis in regards to towing. No information available on my end.
I searched through the entire dealer database for more specific towing information. I wasn’t able to find anything.

>Do I need a GLS580 to tow a 7,000 pound trailer up a big hill, or will the GLS450 suffice?
The GLS450 is more than capable of towing the 7000lb airstream. It is really personal preference to upgrade to the larger engine.

>Does Magic Vision Control need special wiper blades? How much do they cost? Can you get them from any third parties?
Yes, the wiper blades for MAGIC VISION CONTROL® features wiper blades with laser-cut holes that emit a highly precise spray of washer fluid directly in front of the moving wipers. The system eliminates the brief, vision-obscuring spray across the full windshield, and minimizes the overspray and runoff that can reach the passengers during top-down driving. I google searched for aftermarket blades but was unable to find any. The wiper blades from Mercedes are $100.

>Will the 2021 X167 allow you to record the front camera and/or the other cameras like Tesla lets you do?
The GLS with drive assist plus options come with a front multi-function camera specifically for those features. This camera will not record.

 

I spent some time reading the 2020 GLS owners manual. Below is relevant info for towing large loads.

Max trailer weight -> 7716 pounds
Max rear axle weight -> 4080 pounds
Max hitch receiver weight -> 617 pounds

Which autonomous driving features are enabled / disabled when towing:
E-active body control is ENABLED. Can be manually disabled.
Blindspot assist is DISABLED
Active lane-keeping braking actions are DISABLED
AIRMATIC is set to NORMAL Level. Other ride height options are disabled.
Active Speed Limit Assist does NOT adapt to trailer-specific speed limits when towing.
Active Steering Assistance is DISABLED when towing
Active Distance assist is ENABLED but does NOT adapt its behavior when towing.
Rear Parktronic is DISABLED
Drive Away Assist is DISABLED
Cross-Traffic Alert is DISABLED

 

I have posted on the GLE forum about my experiences towing too. If you have not already committed I recommend talking to Andy Thompson at CANAM RV in London Ontario Canada about the various models of MB for towing. He has a great deal of knowledge and experience and loves to talk about towing even if you are not his customer. He has 50 years experience with towing and loves the European SUV tow vehicles and keeps up to date on the newer models.

 

>Will the 2021 X167 allow you to record the front camera and/or the other cameras like Tesla lets you do?
The GLS with drive assist plus options come with a front multi-function camera specifically for those features. This camera will not record.>

The front camera is standard on all US GLSs. If you get the augmented video for nav, the dash cam will be able to be retrofit, if it is not available from the factory on 2021s (which it may be).

 

I also reviewed the Airstream forums where there are a couple discussions of 2020 Mercedes SUV's as tow vehicles.

I now have options figured out for the build I would like, and I'm still trying to finalize between a GLS450 or 580 as the preferred GLS for towing large loads. Here is what I've concluded.

GLS 450 vs. 580:
Both versions of the GLS are mild hybrids, with an electric motor that can augment the gasoline engine's horsepower and torque for a short time. This means that the electric will help deliver better performance during short bursts of acceleration, such as entering a freeway or while passing, but not when towing up a long grade - there is not enough battery capacity for that.

My 2011 GL350 diesel engine has 210 horsepower and 400 foot-pounds of torque.
The 2021 GLS 450 gas engine has 362 HP and 369 foot-pounds of torque
The 2021 GLS 580 gas engine has 483 HP and 516 foot-pounds of torque
Both 2021's have an electric motor that provides an additional 21 HP and 184 foot-pounds of torque for short bursts.

Based on this, my conclusion aligns with what the dealers have said - that if my GL 350 was adequate to tow a 7000-pound Airstream, then the GLS 450 is likely to be adequate as well. The GLS 580 would clearly be a stronger tow vehicle, at the cost of fuel economy during normal daily driving. So it comes mostly down to personal choice vs. necessity as well as cost.

Offroad package:
No one seems to think that there is any compelling reason to choose the Offroad package with the two-speed transfer case for towing. The assumption is that the two-speed is not more heavy duty than the single-speed, and that the single-speed isn't really likely to fail in a 2021 GLS. Plus it sounds like the offroad package is exceedingly rare. So I am going to pass on this option.

Active Body Control:
Active Body Control is not disabled during towing, and most people that have it like it for daily driving, and it can easily be turned down or off for towing. I personally plan to keep the GLS for 10 years, and I'm scared of the eventual repair costs for this option so am going to pass on it. I think this option is more of a personal preference when it comes to towing rather than helpful or harmful.

Autonomous Driving and Safety Features:
Per the chart above, some are disabled and some are active. My philosophy is to load up on safety features, and also on features that keep me from getting into an accident or fender bender given how expensive this vehicle is to repair, so I am definitely ordering the full driver assistance package.

Other considerations:
While it has nothing to do with towing, we really liked the emerald green color, which is almost black when not in direct sunlight, and this color choice makes it a bit harder to find our ideal build since the green color appears to be quite rare. The green color also looks great with the night package and the black 21" AMG wheels, which are apparently both only available on the GLS580 for 2021. So my conclusion is that if I can negotiate a similar percentage discount on a GLS 580 that I can get on a GLS 450, I'm likely to build a 580. My fear is that the dealers will stick to MSRP on the GLS580, while the are already offering to discount the GLS450 by 10% without me even asking.

 

Sounds like you are very well informed to make a good decision. Good luck!

 

Yes, in the US the GLS580 is the only one that comes with the AMG styling (and therefore the ability to get the night package). And I, too, think emerald green is absolutely gorgeous. My fav MB color.

 

I just got a completed build sheet for my gls580.

All smooth plus two interesting items that were not in my copy of the dealer order guide.

The rep added a dashcam - option 21U - that I did not know was available. He said it will record front facing video onto a memory card.

The rep added two options related to towing
550 Trailer Hitch
557 Increased Towing Capacity

​​​​​I don't know if option 557 is meaningful or does anything, but I expect it cannot hurt...

 

Option 557 is part of the trailer hitch option and it doesn't cost extra and cannot be ordered without 550. I think since many of the codes are shared with the GLE which had the increased towing capacity from 7200 with the newer model, but the GLS is the same as the previous model.

 

Thanks for the useful info. I know you posted this several months ago , however, I am looking to buy or build a 450 with certain specs. Inventory is limited for some reason so a build may be my best option. I want the AMG sport package as well as tow package but the dealers in Virginia are saying they stick with MSRP. This is a first for me. I may be better off buying from the dealership you worked with and shipping east. Do you care to share your dealer's contact info.?

 

Sure. franz.krieg@autobahnmotors.com

 

My opinion may not be popular, but here it goes: Mercedes is a complex piece of machinery and I personally would not take advise from an RV shop owner with no background in auto engineering or Mercedes products. I was curious about the hitch reinforcement that they do several years ago. Showed a photo of their reinforcement to my MB service department manager and he said it would void part of my warranty -- FYI, the warranty (plus the extended warranty) has saved me over $12,000 in repairs cost. There was no way I would risk that. When I contacted their shop back then, what concerned me the most was their unwillingness to provide any type of specification for the "reinforced" hitch (They resorted to "you will be fine"). Well, if I am paying them to reinforce a 600# rated hitch, they better tell me how much more weight the hitch can handle (700#? 800#?) or else I am not paying them anything. Also, they weld a brace (at least back then when I contacted them) to the axle carrier, which is problematic (blocks access to the DEF tank, may cause the axle carrier to crack under weight distribution hitch forces, noise bypasses into cabin, etc).

Anyways, I think the GL hitch is pretty good as is, and the best course of action, IMO, is to stay within the 600# rating. I personally think the hitch is overbuilt and can handle a couple of hundred pounds more (I don't recommend anyone exceeding it), but thats my opinion. The hitch has 2 long support arms that go into a recess in unibody and gets bolted there. This makes for a secure hitch/unibody connection and improves weight distribution. Porsche, Audi, and BMW hitches lack these support arms. Also, the hitch receiver box piece goes around the tube and provides fault tolerance. Again, Porsche, Audi, and BMW hitches lack this feature. I have towed a 26 ft trailer that weighs 6000# (travel ready) for the past 5 years. In my experience, GL is very stable, diesel engine provides very good range with 26 gallon fuel tank, brakes are fantastic, and 95% of the time I can tow using the cruise control lever. The only time I take over is when going down steep hills (say, 10% grades), where I manually downshift to maintain speed and avoid using the brakes.

I must say, when our GL retires from towing duties in the next year or two, I plan to buy a pickup. First, I absolutely despise the clip on tow mirrors and would love to have integrated tow mirrors. Second, you can buy a nice Tundra for $40k (less than half the price of a GL), the maintenance cost is also half that of a GL, and the repair cost (doubt you ever need to repair a Tundra) would be a fraction of GL's. Third, a pickup bed gives you a lot more storage (e.g., for lawn chairs or bikes) and is a better place for dirty items (grill, charcoal, firewood, fuel, etc). Forth, pickups have much superior cooling system, integrated brake controllers, tow/haul mode button, larger fuel tanks, numerically larger axle ratios, more weight carrying capacity, and are basically designed for towing/hauling. Finally, I am planning a trip to the national parks out West, and was concerned about MB support. There are some states where there is no MB dealership (North Dakota, Wyoming, and a few more). I do not worry about Tundra breaking down and you can find a mechanic to work on a domestic pickup anywhere in this country (In case you buy a domestic pickup). Anyhow, GL is a very nice SUV and does an admirable job of towing (which is not its main design focus), but there are certainly better options to a GL (when it comes to towing heavy and towing often and for long distances).

 

I recently plan to use GLS 450 to tow a Jayco trailer 264BHW, max gross weight 6500lbs, dry hitch weight 465lbs. I cannot confirm in the owner manual or with dealership that if a weight distribution hitch (WDH) can be used with GLS. I got conflicting opinion from Jayco owner FB group. I thought here might be a better source for using GLS to tow travel trailer. Any input on GLS using WDH?

 

No problem for me on my 2020 GLS580.


Nice and level ready for ther road.

 

So you used a WDH for your GLS580 and no issue with the AIRMATIC or Trailer Stability Assist function of GLS? Which WDH are you using?

 

All works as it should. Airmatic will remain in "Normal height" mode when the trailer is connected even if you choose sport setting. I have the Eaz lift weight distribution hitch with 1000lb rated bars.

 

Most of the replies above are accurate based on my experience.
I towed Airstream 23FB (total weight Approx. 6,000 lbs.) with 2011 GL350 for over 50,000 miles including a road trip to Alaska.
Last year I purchased 2020 Emerald Green GLS 580 with tow package.
I hitched my Airstream using weight distribution hitch. I do not think we need to strengthen the factory hitch
I just drove it to Sedona, AZ and Albuquerque NM about 1700 miles round trip with out any issue.
Got about 15 mpg same as with previous GL350.
My MB dealer keep telling me that 450 will be OK for towing, I decided to go with 580 and I am glad for that.
In my area 580's have very limited inventory and dealer are pushing 450's. I was lucky to find Emerald Green at an out of state dealer
Going over 7,400 ft pass of Flagstaff I could hardly feel the trailer.
I used P2 brake controller mounted under the dash board and hooked to famous green plug (hard to find) buying connector from Trailer Supply
What I said above is base on my experience and opinion and I could be wrong
Enjoy you new Mercedes which ever model you select

 

I would like to share my recent experience driving in a snow storm with my GLS580 pulling 23 Front bed AIRSTREAM coming back from Albuquerque. Living in Southern Calif all my life it was the first experience. Visibility was limited, the car sensors were going crazy, as the snow and ice was covering the front camera and other sensors. Luckily the car performed very well no slipping sliding, although there was no ice on the Hwy except about a foot of snow. It took us 2 hours to cover 30 miles. Did see cars and tractor trailers on each side of road. Due to my excellent driving skills the 30 mile drive was event free. Just kidding, I was soooo scared, could not get off the Hwy. Unable to see any lines on the road, blindly following the big rig, luckily the truck stop cleared the ramps where we stayed for a while. The road was clear rest of the way.
Our made a mistake not checking the weather around Albq which is about 6000 ft, we were checking the weather in Falstaff which over 7000 ft.
Any way it was an experience of a lifetime, for folks who live in snow country may not be a big deal.
Cheers and thanks for sharing my experience

 

I know I’m really late to this thread, but usually if you have specific questions about a Mercedes, a support ticket with the Mercedes-Benz customer assistance center is a good way to get accurate information from the factory.

 

The GLS does not need any special equipment to tow up to its 7716 lbs. The air suspension will sort out any issues up to its max tongue weight (617bs). As any trailer person ought to know, that number is contingent on commensurate reductions of cargo in the truck itself. Maximum axle load is 4078lbs. The hitch is class 4 thus 7700 lbs are well within specs. Mercedes does not recommend tapping the electrical system for a brake controller and I would personally discourage it since once you attach the trailer through the provided electrical connection, essentially every drive system in the car is automatically modified for trailer operation. The GLS should tow a 6000lb trailer with ease, particularly the 580, given much higher torque and better brakes.

 

I am not aware of any Mercedes recommendation not to use a hard wired brake controller. Mercedes does not provide much information on brake controllers that I could find. Could you explain further why you would discourage a brake controller to be connected to the factory provided electrical connection? Mercedes provides a 4 wire plug electrical connection under the dash in the drivers footwell, for the vehicles with the tow package. The ESP trailer stabilization program is activated by plugging the 7 pin trailer connector from the trailer to the receptacle on the hitch, not by the brake controller .

The plug was tucked in above and I pulled it down

Controller set back from air bag panel

 

Great info. But note, it doesn't require tapping into the system. The vehicle already has a connector (which I wasn't aware of). Now that you have shown us its definitely on my to do list! Thanks.

 

Back to the WDH usage on GLS 450. I recently bought an Anderson WDH and found that on the very first page of the manual saying that if your TV has electronic sway control, it might work against the hitch sway control and results in more sway. I called Anderson tech support and they do confirmed that in severe sway situations, these two might not work together and might end up over-correcting the sway and cause more sway. Based on this and also the ambiguity regarding if GLS 450 can or cannot be used with a WDH, I called MB customer service twice and both times, they don't recommend using any WDH or hitch extension for towing with GLS. I also called the service/part manager in my local MB dealer. Again, he don't recommend and cannot comment on the safety of using a WDH on GLS 450. You are at your own risk is what they told me. Based on this, I really wonder for those users using WDH on GLS/GLE, no issue at all?