How to determine Towing power?

[sonic2211]

We are looking for a used 2010-2014 Yukon XL. We would be open to Suburban if we could reach our towing power needed. We need it to be able to pull around 7,000 lbs. What I am running into is that I can find no easy way to determine pulling power. For example, if I'm looking at a 2011 Yukon XL, I know if it's a 6.2L Denali with a 3.42 axle, it can pull 7800-7900 lb (2wd vs awd). But what if it's not a Denali series but it has a trailering package? What can that pull? In this trailering guide (https://letstowthat.com/wp-content/uploads/2020/09/2011-GMC-Trailering-Guide.pdf), there are three options under a Yukon XL 4wd 5.3L, and only the third option can pull 8000 lbs, but it doesn't say if that's with a trailering package or what the difference is between that option and the above two options.

I found this website, but again, it doesn't delineate if something has a trailering package (https://www.autopadre.com/towing-capacity/gmc-yukon-xl)

And is there a difference between a tow package and a trailering package? And what if something is advertised as having a trailering package but they also say the rear axle is only 3.08? I read on one of the forums here that a trailering package should have a 3.42 rear axle.

Thank you in advance for any clarity you can give on this topic!

 

[Foggy]

If you are going to pull 7000 then you will want at least the 3.42 gears...
The 2wd rear axle is heavier duty than the 4wd rear axle.
6.2 engine would be way better for towing power...
The trailer packages may or may not include the built in tow brake controller - you
will have to physically look to see if it is built in - to the left side of the steering wheel

 

[intheburbs]

"Towing rating" is the last question you should be asking. That rating is honestly BS, because it's calculated with a 150-lb driver, and no other cargo or passengers. Is that how you're planning to tow? You should be more concerned with payload rating, GVWR, and axle weight ratings.

I towed a 7,000-lb travel trailer with a half-ton Suburban. Not fun. And stuff broke. Like the rear axle. While on vacation. Multiple times.

Suburbans and Tahoes of that vintage with the HD cooling/trailering package are rated to tow 8100-8200 lbs, so actually slightly more than a Denali XL.

If you're talking occasionally towing, weekend trips to the lake, you'll probably be fine. But if you intend long road trips, hills, mountains... You probably want something heavier-duty.

The 2500 SUVs are the kings of the hill. Unfortunately, given the current used car market, they're gold-plated unicorns and you'll pay through the nose for a good one, if you can even find one.

My suggestion: Lower your expectations a bit, will 5500-6000 lbs work? Half-ton can do that all day.

 

[Geotrash]

I tow a 7000 lb camper (loaded for camping) with our 2012 Yukon XL Denali. It handles it very well, though I’ve made some modifications to it, including a bigger cam, 2-row radiator, a Derale fan-forced transmission cooler, and a billet torque converter that can handle towing duty better. Of these mods, the torque converter is the only one I consider to be essential.

The Denali is AWD so it’s running the power through both axles all the time instead of the rear only as others do when not in 4wd, though it’s possible to upgrade the rear axle to one from a 2WD Escalade (14-bolt vs the stock 10-bolt) and it’s a direct fit swap. So far, I have about 20k towing miles and 130k total on the clock and no issues related to towing.

The Denali is also a 6.2 engine, which I find has plenty of power for pulling our camper anywhere we’ve wanted to go. Took it to Yellowstone last summer in 90° heat across the red desert in southern Wyoming, and have made multiple trips across the Appalachians.

To answer your direct question though, the officia towing capacity of each truck will depend on how it’s equipped. You can paste the VIN numbers of ones your considering into some of the free lookup sites out there and get the details of how it’s equipped.

Most important, in my opinion, is the integrated trailer brake controller, (JL1) because in 2012 and newer models it will work with the stability control system to control trailer sway in an emergency maneuvering situation. Second is the engine oil cooling system (KC4), transmission cooling system (KNP), and the enhanced cooling package (K5L) because it includes 700w fan motors over the regular 500w ones. That said, the 700w motors and fan blades can be added later, as the K5L may be hard to find. I also recommend the 3.42 axle ratio (GU6), the 7400 lb GVWR (C6C) for maximum payload and tow ratings, HD trailering equipment (Z82), and finally the autoride suspension (Z55) because it has self-leveling rear air shocks.

Hope this helps.

 

[Geotrash]

Here’s how ours stacks up on the CAT scales loaded with my wife, 2 kids and gas for camping. I’ve also included our payload sticker to show that we’re within the limits of both axles and the payload capacity of the truck, but only just. We use a Camco Recurve R3 hitch with integrated friction sway control, and have no problems with sway. Note that the tongue weight on the camper comes in at about 700 lbs, so total weight of the camper with propane and all of our gear is actually closer to 7200-7300 pounds. I’ve also pulled it with a generator on the rear bumper of the camper and a full water tank, which together add about 600 more pounds, and couldn’t tell the difference.

 

[swathdiver]

What I am running into is that I can find no easy way to determine pulling power.

Welcome to the forum Sonic. First, I suggest looking for 2012-2014 models because they have Trailer Sway Control, Hill Start Assist and Improvements with Powertrain Grade Braking and Cruise Grade Braking. Like Dave, JL1, the Integrated Trailer Brake Controller is a must have, won't consider a truck without one. No, it cannot be added! LOL

Ok, if you come across a 5.3 and it has 3.08 gears, pass on it. If you come across a 5.3 with 3.42 gears, you have to make sure that it has K5L in its RPO sheet so that you know it is rated for the maximum tow rating. Same goes for the 6.2 Denalis. Some of them do not have the external engine oil cooler and external transmission cooler either.

Sign up to Compnine, $5 for 5 RPO Sheets.

If you are looking for a real unicorn, in 2010 GMC made Yukon XL SLTs with the L9H 6.2, no AFM, and they can be found as 4x4s or RWD. Thus far we've only located just under 40 but they do show up for sale every month or so, usually all but used up mileage wise.

View attachment 364106

We can still see your VIN Dave! LOL

Your girl weighs 100 pounds more than mine! Is that what those Dubs and air suspension add? My payload capacity is 1499 pounds with the same GVW Rating, so her original curb weight was 5901. Right after I put the new Michelins on, the CAT Scales say she weighed 5860.

Question for Dave and Bill @intheburbs @Geotrash : How far on average is your daily run while towing a travel trailer?

 

[Geotrash]

We can still see your VIN Dave! LOL

Eh, that's alright. :-D

Oh, you also asked about our average daily run when towing. About half of our trips are to destinations within 2 hours of home, and about 3-4 times a year we will take a longer trip that's 4-5 hours from home. And once a year we do a major trip, like out to Yellowstone, etc., and will stack on multiple 6-10 hour days in the saddle, with a few long days of 14 hours in the past few years. So the average is probably 3-4 hours a day in the saddle towing.

 

[sonic2211]

Thank you so all so much for your replies. This was super helpful! I'm going to take a little while to digest all of your responses and I may have a few more f/u questions, but I did want to answer one question that I should have answered in the original post. We plan to pull only occasionally -- most of what we will pull will be less than 7,000 (small boat, etc), but we occasionally will need to pull a 7,000 farm tractor/trailer combo but even then, we will only be pulling it for an hour or so on roads with no mountains. We live in Maine so it's never super hot. We may occasionally take road trips to the mid-west but never pulling anything heavy. We do have a family of 6 and plan to have added gear, etc so thank you for mentioning that @intheburbs We eventually may get a camper trailer but will get a light one. So our pulling needs are mostly light but occasionally heavier with the tractor. Most of our driving will be more family oriented, with occasional trips to the back woods of Maine where clearance and 4wd (especially in winter!) will be essential. We use our current 4wd on a Suzuki XL7 quite frequently in our Maine snowy and icy winters! Thank you all again!

 

[intheburbs]

View attachment 364106

Geez...1342 lbs payload?
My family of five, now three adult children including my fat butt, weighs 900 lbs. Wouldn't have much payload left for a trailer.

 

[Geotrash]

Geez...1342 lbs payload?
My family of five, now three adult children including my fat butt, weighs 900 lbs. Wouldn't have much payload left for a trailer.

That's why literally everything we take camping with us goes into the trailer and not into the back of the Yukon. The ONLY things in the Yukon, besides seats and a steering wheel, are 2 adults, 2 small-ish kids (10 and 13), and a 65 lb. dog (all in about 650 lbs. of meat ). We even take the third row out on most camping trips. But again, that 6.2L pulls it all with ease and the truck and camper combo are very stable.

 

[intheburbs]

That's why literally everything we take camping with us goes into the trailer and not into the back of the Yukon. The ONLY things in the Yukon, besides seats and a steering wheel, are 2 adults, 2 small-ish kids (10 and 13), and a 65 lb. dog (all in about 650 lbs. of meat ). We even take the third row out on most camping trips. But again, that 6.2L pulls it all with ease and the truck and camper combo are very stable.

It's not the engine you should be worried about. Based on just the engine, hell, you could pull 15,000 lbs.

First, you have a less-than-optimal axle ratio - 3.42. 3.73, 4.10 or aftermarket 4.56 are better for towing. Second, I've always felt the weak link of the GM half-tons is the rear axle. Semifloater, prone to overheating on long drives with heavy loads. My 2001 Suburban is wearing rear axle number 4 precisely because of heavy long-distance towing. Third - weak half-ton brakes. The half-tons are underbraked. But I would expect with the 20s, you'd have the clearance to upgrade the size of your rotors.

Lastly, for those with newer GMT900s - don't get complacent and think the truck and integrated trailer brake will get you out of a death-sway. Make sure you've trained yourself to manually apply the trailer brakes in case of sudden/excessive sway. You have to pull out of excessive sway - you need tension on the hitch. You accomplish that by either mashing the gas (EXTREMELY counter-intuitive) or manually applying the trailer brakes. Practice it to a point you can do it instantly, without looking.

 

[Geotrash]

It's not the engine you should be worried about. Based on just the engine, hell, you could pull 15,000 lbs.

First, you have a less-than-optimal axle ratio - 3.42. 3.73, 4.10 or aftermarket 4.56 are better for towing. Second, I've always felt the weak link of the GM half-tons is the rear axle. Semifloater, prone to overheating on long drives with heavy loads. My 2001 Suburban is wearing rear axle number 4 precisely because of heavy long-distance towing. Third - weak half-ton brakes. The half-tons are underbraked. But I would expect with the 20s, you'd have the clearance to upgrade the size of your rotors.

Lastly, for those with newer GMT900s - don't get complacent and think the truck and integrated trailer brake will get you out of a death-sway. Make sure you've trained yourself to manually apply the trailer brakes in case of sudden/excessive sway. You have to pull out of excessive sway - you need tension on the hitch. You accomplish that by either mashing the gas (EXTREMELY counter-intuitive) or manually applying the trailer brakes. Practice it to a point you can do it instantly, without looking.

Thankfully I have had better luck with rear axles. Both my 2007 and 2012 XL Denalis are still wearing their originals, with 130K and 220K, respectively. I attribute their longevity to the fact that the AWD system is sharing the work with the front axle, full time, and that I change the fluid every 20K or so. I agree that 3.42 is suboptimal, but is helped by having a 6-speed at least.

I find the brakes on both of my Denalis adequate for my towing purposes. I'm running ceramic pads and Powerstop rotors on the 2007 and still have the original pads and rotors on the 2012 with lots of life left. I also use engine braking to keep from heating up the brakes too much in the mountains. Back in the 90s I hauled an industrial centrifuge (weighed about 8000 lbs with a gooseneck trailer) all over the western US behind a brand new '95 Chevy 3500 dually with the 454. These Denali's will out pull and out stop that pig any day of the week and twice on Sundays, so it's all relative. The GMT900 is a solid towing platform if you keep it within its limits.

All of that said, I've been looking at upgrading to the 14-bolt rear axle from a 2WD Escalade. They're widely available and inexpensive, but will likely only pull the trigger if I have any trouble with mine. I'll also likely upgrade the brakes on the 2012 once the originals wear out. It's an easy upgrade and yes, larger rotors will fit behind the 20s nicely.

 

[swathdiver]

First, you have a less-than-optimal axle ratio - 3.42. 3.73, 4.10 or aftermarket 4.56 are better for towing.

How do you like the 3.73s for towing Bill? They pull down the rpms about 5 mph compared with the 3.42s so 4th gear at 70 mph is 3000 rpms, which is 3000 @ 65 mph with 3.73s in 4th.

 

[intheburbs]

How do you like the 3.73s for towing Bill? They pull down the rpms about 5 mph compared with the 3.42s so 4th gear at 70 mph is 3000 rpms, which is 3000 @ 65 mph with 3.73s in 4th.

The 6.0 loves to rev. I'm usually in 4th when towing heavy on the highway. I let her eat! I always tow heavy in "M," because I don't want it gear-hunting. On steeper grades I'll wind it higher, letting the VVT kick in for a little extra power boost.

What drove home the importantness(?) of axle ratios is the comparison between my two trucks.
Sierra Denali - 5500 lb curb weight, 3.42, 400 HP
Suburban 2500 - 6500 lb curb weight, 3.73, 350 HP, Blackbear tune

I've never actually raced them head to head.
Denali - 1000 less pounds, 50 more HP, AWD
Suburban - better axle ratio, Blackbear tune

No contest, right? But from my obviously extensive wheel time behind each, I actually think it's pretty close. Here's my expectation of the result of a drag race from a light...

Denali jumps out to an early 1- or 2-car length lead. But after about 30 MPH, the Suburban slowly starts to close. The higher ratio keeps the engine higher in the power band. Probably around 70-80, the Suburban pulls even, then at 100 the Denali hits the governor and the Suburban walks away on its way to 120+. Seat of the pants 0-60 times? I'd say 6 flat for the Denali and 6.2-6.3 for the Suburban.

Yes, the tune firmed up shifts and increased throttle response, but the 10% difference in gear ratios is the difference, IMHO. Simple gear change offsets 50 hp and 1000 lbs.

Having the two GMT900 trucks allows me to make some good comparisons. Another eye opener was the effect of tow vehicle wheelbase on towing smoothness and stability. I also have a 6x12 enclosed single-axle cargo trailer I tow frequently. Usually I tow it with the Suburban. It's about 4,000 lbs, and has no trailer brakes. The Suburban has a 9900-lb braking system (RPO JH6), so it's better suited for towing the trailer. The ride is pretty choppy, especially on the ****** Michigan highways like I-94. But then one time I towed the trailer with the Denali. Even though it is 1000 lbs lighter, the extra 14 inches of wheelbase made for a remarkably smooth tow. I was shocked at the stark contrast. Again, the Denali brakes aren't really up to the task, but frankly I'd rather tow that trailer with the half-ton, rather than the 3/4-ton.

 

[Mickey_7106]

Everyone makes great valid points. I have little experience towing but did drive a 14k lbs Rv, so take my recommendations with a grain of salt. I had very little wiggle room when loading up the rv to camp.

You'll probably want some E Load rated tires at minimum. Upgrade your brake pads to HD/towing rated. Tow air bags for the rear or a hitch weight distribution. Think I read that increases your town capacity to 12k lbs? Also everyone is talking about coolers but since it snows where you live you might want to consider one of those remote oil thermostat units.

 

[Geotrash]

Also everyone is talking about coolers but since it snows where you live you might want to consider one of those remote oil thermostat units.

^^^YES.

That's precisely why I went with the Derale 13960 cooler. It has a thermostatically controlled fan so that the fluid heats up to operating temperature faster, but the fan cools it down before it gets too hot. It's the best solution I've found for these trucks when towing heavy in the summer heat. It outperforms the factory cooler under load but doesn't have the downsides that the Trucool 40k does, which doesn't allow the fluid to heat up enough in the winter (GM says 150ºF is the minimum recommended operating temperature for the 6L80E), and blocks too much airflow through the radiator, creating an engine cooling problem when towing heavy in the summer. I mounted the Derale below and behind the front bumper, so it's out of the path of airflow through the radiator and it works great.

 

[Just Fishing]

^^^YES.

That's precisely why I went with the Derale 13960 cooler. It has a thermostatically controlled fan so that the fluid heats up to operating temperature faster, but the fan cools it down before it gets too hot. It's the best solution I've found for these trucks when towing heavy in the summer heat. It outperforms the factory cooler under load but doesn't have the downsides that the Trucool 40k does, which doesn't allow the fluid to heat up enough in the winter (GM says 150ºF is the minimum recommended operating temperature for the 6L80E), and blocks too much airflow through the radiator, creating an engine cooling problem when towing heavy in the summer. I mounted the Derale below and behind the front bumper, so it's out of the path of airflow through the radiator and it works great.

I was thinking about that pretty seriously.
I added a bigger cooler that worked great in the summer, but in the winter the fluid was pretty close to body temperature after a good drive.

Luckly on my S10 the grill is really easy to pull.

So, during the winter I just tape off part of the cooler in order to get the fluid above 100f


On the HoeMare,
For my new cooler setup, I'm thinking about going with a Y for the feed and return.
One feed will go to the radiator cooler.

The other feed will go to the cooler in the front of the radiator.
On that line, add a little valve to control the flow.

That way I can both control the back pressure I'm reading, and the transmission fluid temperature.
(And the pressure reading comes off of the feed line going into the cooler line filter.)

Overthinking it, but I'm thinking what the hell!

For my transmission cooler, I have a double pass 1/2in unit that's a left over from my garage air system/compressor install.
It was going to act as an air cooler/water separator, but I went a different route instead.
I'm curious to see how it does as a transmission cooler.

This will also allow me to see the resistance difference between the radiator and the front cooler setup with the lines plumbed with -8AN.

 

[donjetman]

Both Derale and Tru-Cool sell thermostat bypass valves for cold wx climates.

 

[sonic2211]

Welcome to the forum Sonic. First, I suggest looking for 2012-2014 models because they have Trailer Sway Control, Hill Start Assist and Improvements with Powertrain Grade Braking and Cruise Grade Braking. Like Dave, JL1, the Integrated Trailer Brake Controller is a must have, won't consider a truck without one. No, it cannot be added! LOL

Ok, if you come across a 5.3 and it has 3.08 gears, pass on it. If you come across a 5.3 with 3.42 gears, you have to make sure that it has K5L in its RPO sheet so that you know it is rated for the maximum tow rating. Same goes for the 6.2 Denalis. Some of them do not have the external engine oil cooler and external transmission cooler either.



Sign up to Compnine, $5 for 5 RPO Sheets.



If you are looking for a real unicorn, in 2010 GMC made Yukon XL SLTs with the L9H 6.2, no AFM, and they can be found as 4x4s or RWD. Thus far we've only located just under 40 but they do show up for sale every month or so, usually all but used up mileage wise.


We can still see your VIN Dave! LOL

Your girl weighs 100 pounds more than mine! Is that what those Dubs and air suspension add? My payload capacity is 1499 pounds with the same GVW Rating, so her original curb weight was 5901. Right after I put the new Michelins on, the CAT Scales say she weighed 5860.

Question for Dave and Bill @intheburbs @Geotrash : How far on average is your daily run while towing a travel trailer?

View attachment 364113

I am wondering about whether what you mentioned as being important in the 2012-2014 models is really a deal breaker? I have found a 2011 Yukon XL Denali with <140,000 miles that has JL1, KC4, KNP, Z55, C6C, GU6, Z82, VR4. So trying to determine whether I really need the upgrades in the 2012-2014 models that you mentioned. That being said, I also found a 2012 Yukon XL Denali with a bit more mileage ~150,000 and a couple thousand more in price with the same line up of RPO codes. Is it worth it to buy the 2012 model??

 

[swathdiver]

I am wondering about whether what you mentioned as being important in the 2012-2014 models is really a deal breaker? I have found a 2011 Yukon XL Denali with <140,000 miles that has JL1, KC4, KNP, Z55, C6C, GU6, Z82, VR4. So trying to determine whether I really need the upgrades in the 2012-2014 models that you mentioned. That being said, I also found a 2012 Yukon XL Denali with a bit more mileage ~150,000 and a couple thousand more in price with the same line up of RPO codes. Is it worth it to buy the 2012 model??

You'll have to answer that one for yourself, can you live without TSC and HSA and the cruise control changes? How about the upgraded navigation unit? If you have a good sway control and weight distribution hitch then those things aren't as critical to have, just nice to haves and you'll have a little more jingle in your pocket!