In Tow

Testing the GMC Yukon Hybrid, Toyota Tundra

Published in the September 2008 Issue September 2008 White Out & Wide Open—The Blog, Snow Tests Viewed 2076 time(s)
"A display screen shows which mode the vehicle is in, depending on how the Yukon Hybrid is being driven, i.e., stop and go traffic, downhill, uphill, towing, etc. The Hybrid Power mode means it's running on electric and gas, Engine Power mode that it's strictly running of fuel and Battery Charging when the battery is being recharged, which happens when decelerating or stopping.

We've spent a lot of time, effort and space on towing tips, snowmobile trailers and what we like about our favorite riding areas, but not so much on actually getting to where we like to ride.

You know, like what we're going to tow with.

SnoWest Magazine did cover the unveiling of the new Toyota Tundra ("Toyota Unveils Full Size Pickup," SnoWest, February, 2007, page 28) and test drove the Volkswagen Touareg ("Test Drive: VW Touareg," SnoWest, December, 2007, page 76) and now can add another vehicle to our list of towing tests and update one already there.

So far this year we've test driven the 2008 GMC Yukon Hybrid and 2008 Toyota Tundra 4x4 Double Cab with a 5.7L V8.

We are lined up to possibly add a couple more to our towing test list, which we'll cover in later issues, but we were anxious to include the Yukon and Tundra in this issue since we're once again presenting our Trailer Showcase.

While we would prefer to conduct a tow test in the winter in what we consider real world conditions, we're not going to refuse to test drive a new SUV or truck just because it's summer. So that's why we had those vehicles this past summer.


Loadin' Up

We loaded our two-place Triton Trailer with a 2008 Arctic Cat M1000 and 2008 Polaris Assault, which, all totaled put the weight of everything in the 2,000-pound range. That wasn't close to either the Yukon Hybrid or Tundra's maximum towing capacity of 6,000 lbs. and 10,300 lbs., respectively. But at least it's a consistent comparison. Last year, when we tow tested the VW Touareg, we used a four-place enclosed trailer with two sleds that tipped the scales at about 7,520 lbs. That would have been over the limit for the Yukon but a good test for the Tundra.

Regardless, we hooked on to the trailer and went to the Conant Hill in Swan Valley, ID, for our test. The hill has a 6 percent grade and our test run was a little more than a mile. Rather than rely on the vehicle's speedometer, we use a satellite-based GPS excelerometer for accuracy. As a side note, the Yukon Hybrid's speedometer was just about right on with the excelerometer but the Tundra was off by about 2-3 mph.

See chart No. 1 for the results of the hill towing test. We also did a 0-60 mph test. With the Yukon Hybrid, we were able to borrow a 2008 Yukon Flex Fuel vehicle for comparison. After we turned the Yukon Hybrid back in to GMC, we figured we should have done a 0-60 mph test with the trailer attached but that was a little too late. We did perform that test with and without a trailer on the Yukon.

As the charts show, the Tundra pretty much cleaned up on the Yukon. On the trailer towing test up Conant Hill, the Yukon's best time was 73.5 mph while the Tundra blew up the hill, hitting 86.5 mph (the vehicle's speedometer said 88 mph). You can also see on the 0-60 mph test the results were about the same with the Tundra showing its might.

Horsepower Edge

Granted, the Tundra, with its 5.7L V8, has the edge in horsepower with 381 and 401 lb. ft. of torque compared to the 6.0L V8 Yukon Hybrid's 332 hp and 367 lb. ft of torque. And the Yukon Hybrid is about 200 lbs. heavier in curb weight.

While it's not a real fair comparison, simply because of the trailer's weight difference, just to throw out the VW Touareg's numbers from a year ago on the same hill, that vehicle hit 71.9 mph at the top of the hill.

While we don't think those towing numbers cast a huge shadow over the Yukon Hybrid, if you're looking for a ray of sunshine, check out this GMC's fuel economy figures compared to the Tundra. Because of the Yukon Hybrid's unique and patented two-mode hybrid propulsion system, it shines in the fuel economy area when you consider it's a full-size SUV. Its 20 mpg city and 20 mpg highway numbers are better than the Tundra's 13 mpg city and 17 mpg highway numbers.

Those differences are about the same when towing a trailer, too. The Yukon Hybrid was averaging about 11-12 mpg on the highway (it runs in the V8 mode when pulling at highway speeds), while the Tundra got 8-10 mpg. The real difference is if you have to do any city or other stop and go driving or low speed driving. That's when the Yukon Hybrid runs mostly on electric power and uses virtually no fuel, if any at all.

Breaking that down into terms of dollars, according to, if gas cost $4.10 per gallon, it costs $7.32 to drive the Tundra 25 miles while using 1.79 gallons of gas. The Yukon Hybrid, in comparison, costs $5.12 to drive the same distance while using 1.25 gallons of fuel.

So each vehicle has its unique and very distinctive advantages. It was fun to try each one in various different conditions in addition to the tow test.

Here are our impressions of each vehicle.


2008 GMC Yukon Hybrid

The Yukon Hybrid has some very interesting and nifty engineering and created lots of comments from those who rode in the vehicle with us. One of the most telling comments came when we were unloading some boxes and other stuff inside a convention hall this summer. No one around the vehicle knew it was even on despite the fact the Yukon Hybrid was running the entire time we were in the building.

Here's how the Yukon Hybrid's Vortec V8 engine works:

It features a two-mode full hybrid system that, according to GM, is the first in an SUV.

First Mode: Used at low speeds and light loads. The vehicle operates in three ways: electric power only, engine power only, or a combination of electric and engine power. Fuel consumption is reduced in stop-and-go traffic by shutting off the engine for extended periods and running exclusively under electric power at low speeds. Low speeds are defined as between 20-30 mph.

Second Mode: Used primarily at highway speeds. Full V8 engine power is used when conditions demand it-such as passing, trailer towing or climbing steep grades. But the electric motors and electronic controls also help reduce fuel consumption even at highway speeds.

When less power is needed, the vehicle's Active Fuel Management Technology automatically shifts from eight to four cylinders, which is another way fuel efficiency is improved. Another huge factor in making the Yukon Hybrid as fuel efficient as possible is what's called the Auto Stop mode. Essentially what this does is, when the vehicle reaches 0 mph, the gasoline engine is automatically shut down. Now it is running on electric power, which it will continue to do in heavy stop-and-go traffic. Then, when extra power is needed, the engine restarts so it can deliver the needed power and torque. We were very impressed at how seamless this transition was and not even noticeable.

In fact the only way you might ever notice the switch is by following which mode the vehicle is in by watching a monitor on the dashboard, which is also where the navigation system is viewed. When the vehicle is running on electric power the vehicle (made up of icons of an engine, battery, transmission and wheels) on the monitor turns green (of course). One SnoWest SnowTest staffer commented, "It's all about being green these days. When the power display on the video screen shows the vehicle is under engine (V8) power, it shows in orange. But when the vehicle is on hybrid power everything turns to a green color scheme."

The electric power is supplied by a 300-volt battery pack that fits under the second row bench in the vehicle. The batteries are automatically charged by the V8 engine so there is no need to plug in anything overnight. The batteries recharge during deceleration and while braking. According to GM, "regenerative braking" recaptures some of the energy from the moving vehicle when coasting or braking and turns it into electrical energy. The owner's manual states, "This energy is then stored in the vehicle's Hybrid Energy Storage System for later use in the hybrid system, contributing to increased fuel economy."



The hybrid system also relies heavily on GM's new electrically variable transmission (EVT), which uses two 60 kW electric motors, three planetary gearsets and four traditional hydraulic wet clutches to continuously allow variable operation, meaning it manages power whether at low or high speeds.

Lest anyone think the Yukon Hybrid is weak on power because of the electric part of the hybrid equation, you just need to remember that it's a V8.

Our general impressions of the Yukon Hybrid during towing were that it did an excellent job of pulling the trailer and never felt "squirrelly" or like the trailer was more in control than the SUV. The vehicle never felt lacking in power until, of course, we compared it to the Tundra, but even then it was adequate.

The Yukon Hybrid was fun to drive and we really were impressed with the gas mileage it got. At the time we turned the vehicle back to GM, we had driven 1,389.6 miles and used 71.1 gallons of fuel for an average of 19.5 mpg, which included highway and city driving as well as towing.

Of course, the vehicle had all the amenities you'd want, including leather (and heated) seats, an entertainment system (drop-down DVD player) in the back for the kids, a navigation system, XM Satellite radio, a camera to assist in backing up to a trailer with the display showing on the same screen as the navigation system, and the list goes on. Honestly, we didn't have the vehicle long enough to try out all the gadgets it had.

The model we drove had a suggested MSRP of $56,045, which is a fair bit more than the non-hybrid Yukon.

2008 Toyota Tundra 4x4 Double Cab with a 5.7L V8

There's not much new to report on the Tundra other than what we wrote last year in the February issue of

SnoWest ("Toyota Unveils Full Size Pickup," page 28), detailing our first test drive of the pickup. Toyota did add more models to the Tundra lineup but the engine and other things that make it "go" are pretty much the same.

While there are no real updates on the Tundra as far as specs and all that kind of technical stuff, we do have some additional driving impressions.

In case you missed that original driving report we did last year, we test drove the new Tundra on the freeways and backroads of northern Kentucky, which was all fine and nice, but it wasn't mountain driving. On that first test drive we didn't get to pick the driving location but this summer we did and it was the mountains of eastern and central Idaho, which gave us a better handle on how the Tundra would, well, handle the mountains. The only thing missing was the snow.

Ironically enough, one of the driving impressions we most want to talk about in this report was one we had touched on in our February, 2007, feature-fuel economy. In February, 2007, we talked about Toyota's ambitious plans to sell 200,000 trucks last year and how that was pretty ambitious considering truck sales in the United States were down 14 percent from the previous year. Then we wrote, "However, falling gas prices helped spur sales, which increased in October, 2006, compared to a year ago."


That's What You Call Ironic

Now that's irony if there ever was any. As we write this test drive report in July for the September issue of SnoWest, gas prices are at an all-time high in the United States-averaging around $4.10 a gallon for regular, nearly a buck more than it was a year ago at the same time.

As sales figures released this summer show, not even Toyota is immune from those kind of gas prices, as it was widely reported that Toyota would stop production of its full-size trucks at its San Antonio, TX, plant for three months, beginning in August. According to one news report, Tundra sales dropped 54 percent compared to a year ago.

It's those kinds of fuel prices that make two numbers about the Tundra stick out like neon lights on a dark desert night. Those are: 13 city mpg and 17 highway mpg. And after more than a 1,000 miles of driving in all kinds of conditions (except snow) we can verify those numbers are pretty darn accurate. Granted, those are painful numbers when gas prices are the way they are, but what's really going to grab your attention is when you hook on a trailer and tow a couple of snowmobiles. We hauled a two-place trailer from Idaho Falls, ID, to Preston, ID, this past summer and on the drive to Preston, the Tundra averaged 8-10 mpg. Yea, ugh.

Enough with the doom and gloom. Let us just say if you can handle the fuel prices, the Toyota Tundra can handle the towing. This truck is a beast when it comes to towing a trailer. The 5.7L V8 kicked the butt of any hill or mountain we put in its way. The Tundra didn't even hesitate with the two-place trailer loaded with two sleds. That was evident when we tackled Conant Hill in Swan Valley, ID, one of our favorite places to take a vehicle to see its pulling power. Conant Hill offers us a chance to see how a vehicle handles a long pull. It further made its stamp on being a capable tower over Emigrant Summit on Idaho Highway 36 between Preston and Montpelier. While that pass isn't necessarily steep, it does have lots of curves where you decelerate and then accelerate again coming out of the turns. The Tundra never missed a beat even with the trailer.


We'll Pass

It was over Emigrant Pass as well as Bannock and Lemhi passes (both over the Continental Divide between Idaho and Montana) that we were able to use the 6-speed automatic transmission's "manual" feature. Toyota probably doesn't refer to it as a "manual," but when you shift it from automatic to what we refer to as "manual" you have six gears you can work with, from first to sixth. The range of these gears is pretty impressive, as we discovered going up and especially down the steep passes.

We were also impressed at how quiet the vehicle is from inside the cab. It is a very solid truck with no outside noise able to get into the cab. We also liked how the truck hugged the road, even on the tight, windy curves over the passes.

The Tundra we test drove didn't have all the frills the vehicle we test drove in Kentucky did, such as the navigation system and backup feature, but it did come with the tow package and TRD Offroad package, which essentially consisted of a better suspension and tires and engine and fuel tank skid plates. The model we tested was more than adequate for what we like to drive.

Coming off our multi-day test drive, the one thing that really stood out, though, was the excellent horsepower and pulling ability of the Tundra. All of the SnowTesters agreed that the Tundra has plenty of power and we never did feel like we were pulling a trailer.

The model we test drove has a MSRP of $36,772. 

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