Yukon working right? Really struggles to tow my trailer in the mountains.

[broken08]

I have an 07 yukon XL Denali 6.2L. I use it to tow my relatively small and light travel trailer camper. It's only 18' long, single axle, about 4000-4300 pounds loaded down with everything. So this isn't even half of the towing capacity of this supposed beast of an engine and SUV.
I tow in the mountains outside of Denver and head west over the mountain passes a good bit. Anyway, this this will sit at near redline for sometimes 3 minutes straight on these long climbs. Trans temps hitting 260s, water temp moves (and holds) from 12 o'clock to about 2 o'clock.
It always makes it (except the 3 times where it has randomly died unrelated to anything with no codes) but it is freaking working itself.
I bought thise because it was the most powerful SUV, but apparently I need something more powerful.
I swear I see people with Jeep cherokees pulling trailers 10 feet longer. How on earth do those guys do it and mine is about to explode?

 

[kbuskill]

I have an 07 yukon XL Denali 6.2L. I use it to tow my relatively small and light travel trailer camper. It's only 18' long, single axle, about 4000-4300 pounds loaded down with everything. So this isn't even half of the towing capacity of this supposed beast of an engine and SUV.
I tow in the mountains outside of Denver and head west over the mountain passes a good bit. Anyway, this this will sit at near redline for sometimes 3 minutes straight on these long climbs. Trans temps hitting 260s, water temp moves (and holds) from 12 o'clock to about 2 o'clock.
It always makes it (except the 3 times where it has randomly died unrelated to anything with no codes) but it is freaking working itself.
I bought thise because it was the most powerful SUV, but apparently I need something more powerful.
I swear I see people with Jeep cherokees pulling trailers 10 feet longer. How on earth do those guys do it and mine is about to explode?

What gear ratio is your rear axle?

 

[intheburbs]

You do realize you can drive slower than the speed limit, yes?

I've pulled a 7,000-lb trailer through the Eisenhower Tunnel, and on the last ascent approaching the tunnel from Silverthorne, the truck seemed to find its sweet spot right at 4000 RPM and 40 MPH in second gear. And even at those speeds, my trans was running at 235° and the engine was around 220°. I recently pulled an 8600-lb trailer over Powder River Pass in Wyoming, and my trans got up to 241°. But again, I was going slow and steady at 40 MPH.

Weight isn't the only factor in how your truck pulls; in fact it's probably not the biggest factor. Air resistance is also a biggie. You're pulling a brick through the air, and the faster you go, the more wind resistance you get. Doesn't matter what it weighs, it's a great big un-aerodynamic rectangle.

Also, at those altitudes, the thinner air reduces the power output of your engine. Just like you get more easily winded up at Steamboat Springs, your truck gets winded, too. Your "beast" 400-HP engine becomes a wheezing little V6 putting out ~268 HP when you're up at the Eisenhower Tunnel. In fact, your Denali is only putting out about 340 HP just toddling around Denver.

You need to slow down. I let both my trucks rev regularly, but I'd never let them go that high, that long, letting them get that hot. Especially the all-aluminum 6.2. It's a performance engine, not a towing/hauling engine. That's why the GM 2500 trucks get the iron-block 6.0, not the 6.2, even though the 6.2 has 50 more horsepower.

I lived in Colorado for ten years (Broomfield, Westminster and Thornton), so I'm very familiar with altitude and engine power, and I-70 and mountain driving.

ETA:If you want something with more power, get a diesel. Forced-induction engines don't suffer as much power loss at altitude.

 

[gat0r]

^ good info



& OP
you are running it a bit hard... you shouldnt need to see trans temps that high. get a trans cooler or if you have one...a better one (tru cool - get one above your GVW)


how often do you check fluids? maybe they need chg'ing

how does it drive w/o trailer @ altitude?


those jeeps prolly have better upgraded supporting mods.

what gearing do you have?
do you have max towing pkg?
how many miles on it?
what other maintenance does it need?
are teh catalytic converters good?


if its tip top... gear change or a supercharger could help