For 2010, Yukon XL gets upgraded with OnStar 8.2, USB input, E85 capability on all 5.3-liter engines, and the single-speed all-wheel-drive system.The 6.2-liter engine adds active fuel management that shuts off some cylinders in low-load driving, and Denali gets a taller axle ratio for better highway mileage.The Yukon XL was completely redesigned for 2007.

The Yukon XL is a great choice for anyone towing cars, boats, horses, and travel trailers with an SUV.Maximum towing capacity is 8100 pounds for a Yukon XL 1500 model, or 9600 pounds on a Yukon XL 2500; subtract 2500 pounds if the Yukon is fully loaded with people and cargo.With its long wheelbase and heavy-duty construction, the Yukon XL is a stable platform for towing while offering the interior cargo advantages of a full-size SUV.

Like Suburban, Yukon XL is offered in half-ton or three-quarter ton capacities.Yukon XL is also available as a luxurious Denali model that compares well to Cadillac's Escalade ESV.Denali comes equipped with automatic rear load-leveling.

Inside is a comfortable cabin.We found the Yukon XL's optional leather seats comfortable.The driver sits way up high for a commanding view of the road, and the pedals power-adjust to fit short and tall drivers.The instruments and gauges are best in class, elegantly clean yet very functional.Interior small items storage is intelligently designed and all over, including a huge center console.

Second-row passengers will find a lot of leg room in the Yukon XL.Heated bucket seats with a center console between them are available for the second row, turning them into first-class accommodations; and there is a power folding option, making it easier for third-row passengers to climb by.There's even decent legroom and good headroom in the third row.

Yukon offers a choice of engines.GM's trusty 5.3-liter Vortec V8 is the standard choice and it's a good one, making 310 horsepower and 335 pound-feet of torque.We enjoyed its smooth power.The 5.3-liter gets an EPA-estimated 14/20 miles per gallon City/Highway.Flex-fuel versions of the 5.3-liter V8 are available that can run on E85 ethanol, though use of less-efficient ethanol drops fuel economy to an EPA-estimated 10/16 mpg City/Highway.

A 6.2-liter V8 with variable valve timing, delivering 395 horsepower and 417 pound-feet of torque is optional for Yukon XL 1500-series models.A superb engine for towing, the big, powerful 6.2-liter is EPA-rated at 12/19 mpg.

At the top of the Yukon XL line is the Denali, a luxury model with a 403-hp V8.The Denali is offered with two-wheel drive or all-wheel drive, the latter an excellent aid for inclement weather but not designed for serious off-road use.The Denali comes standard with the AutoRide active electronic suspension, which is optional on the regular Yukon XL.The Denali models come with a 6.2-liter V8 that produces 403 horsepower and 417 pound-feet of torque and gets an EPA-rated 12/19 mpg with all-wheel drive.

For 2010, Yukon XL is available with all-wheel drive (also on Denali), or a four-wheel drive system with low range with a full-time position that can be used on dry pavement.Yukon XL is also available with 2WD.All Yukon XL and Denali models use a six-speed automatic transmission.They all have a Tow/Haul mode that reduces upshifting and downshifting, and also shifts quicker, so the transmission doesn't work so hard when pulling a big load.Transmission oil temperature is part of the instrumentation.

Convenience features include a power rear liftgate, a 14-speaker Bose sound system, a navigation system, and a DVD rear-seat entertainment system.Rearview cameras are standard with navigation and available for others with display in inside mirror.

Yukon XL competes with the Ford Expedition EL, Chevy Suburban, and, if cargo space isn't as important as tow rating, the Toyota Sequoia.Yukon XL Denali alternatives include the Lincoln Navigator L, Cadillac Escalade ESV, and Mercedes-Benz GL450.

Virtually ever major mechanical component, including the engine, transmission, axles, suspension, steering, brakes, wheels and tires is different on the 2500-series Yukon XL.Yukon XL 2500 models come with a 352-hp 6.0-liter V8 with 382 pound-feet of torque, a six-speed automatic, and rear-wheel drive or four-wheel drive.

The Yukon XL SLE 2WD ($41,490) and 4WD ($44,330) and the better-equipped SLT 2WD ($46,030) and 4WD ($48,765) come standard with a 5.3-liter V8.A 6.2-liter V8 is optional ($1,000).

The Yukon XL 2500 SLE 2WD ($43,110), SLE 4WD ($45,950), SLT 2WD ($47,510), and SLT 4WD ($50,355) come only with a 352-hp 6.0-liter V8 with 382 pound-feet of torque, a six-speed automatic, and rear or 4WD.

SLE1 standard equipment includes cloth upholstery; dual-zone manual climate control; auxiliary rear AC; AM/FM/CD/MP3/XM six-speaker stereo; Bluetooth; cruise control; OnStar Safe & Sound with one year subscription; driver information center; power windows/locks/heated mirrors with manual folding; leather-wrapped, tilt steering wheel with audio controls; 40/20/40 split front bench seat; six-way power driver's seat; 60/40 split folding second-row bench seat; 50/50 third-row split folding seat; automatic headlights; roof rails; side steps; locking rear differential; three power outlets; P265/70R17 all-season tires on bright aluminum wheels; tow package (receiver hitch, seven-pin wiring harness); intermittent rear wipe/wash; and floor mats.4WD models also get an aluminum-block engine, 3.42:1 axle ratio, and front tow hooks.Options for Yukon XL SLE1 are a Convenience package ($1060) with adjustable pedals, remote start, rear park assist, rearview camera; fog lamps and tow hooks for 2WD ($190); CD changer audio upgrade ($295); integrated trailer brake controller ($200); Z71 off-road package ($230); two-speed transfer case ($100); 20-inch wheel packages; rear-seat entertainment ($1295); and towing package ($230).SLE2 adds three-zone climate control, rear audio controls with headphone jacks (you supply headphones), power front bucket seats and center console, and Bose sound system.

SLT1 models add three-zone automatic climate control, Bose audio system, auto-dimming inside mirror, rear park assist, remote start, adjustable pedals, and universal remote.SLT options include Autoride suspension with rear self-leveling ($1120), the 6.2-liter engine ($1000) and second-row bucket seats ($590).

SLT2 adds leather upholstery (vinyl third row), more adjustable front seats and driver memory, power liftgate, heated front and second row seats, and power folding mirrors w/signals and parking tilt-down.Options include the Sun Entertainment Destination package ($4890) with navigation, rear-seat entertainment, and moonroof; third-row screen ($600); power side steps ($1095); Preferred package ($675) with rain-sensing front wipers and power liftgate; 20 or 22-inch wheels; rearview camera in mirror ($450); heated/cooled front seats ($650); Blind Zone Alert ($500); and power release second-row bench ($425).

Denali ($55,665) and Denali AWD ($58,750) come with a 6.2-liter V8 and Autoride active electronic suspension with rear load-leveling.Denali models come fully loaded, with a wood and leather-wrapped, heated, power-tilt steering wheel; heated first- and second-row seats; 12-way power front seats with lumbar adjustment; memory for the driver's seat and mirrors; power-folding second-row seats; removable three-passenger split-folding third-row seat; power-folding exterior mirrors with integrated turn signals, driver's side auto-dimming and reverse tilting; rain-sensing wipers with heated washers; power liftgate; roof rack, Bluetooth; 10-speaker Premium Bose Centerpoint Surround Sound System; added noise insulation and cooling capacity; and 20-inch wheels and tires (18-inch wheels are available for a $995 credit, for poor roads, tire chains, etc.).

Options are limited to those in the Sun, Entertainment and Destinations Package ($2,390) or separately.Among them: rear entertainment ($1295), third-row screen ($600); power side steps ($1,095); 22-inch wheels ($2795); and Side Blind Zone Alert ($500).

Safety equipment on all models includes dual frontal airbags, head-protecting curtain side airbags, four-wheel-disc anti-lock brakes with electronic proportioning, and StabiliTrak, GM's electronic stability control with anti-rollover mitigation and traction control.Options include rear park assist, two rearview camera choices, and on Denali, Side Blind Zone Alert.Side airbags are not available.The XL earned the maximum five stars in the government's head-on crash tests.Optional all-wheel drive enhances safety in foul weather.

The Suburban and Yukon XL are familiar vehicles on the road.They share sheetmetal body panels but differ in details such as the grille, bumpers and lamps.These are big boxes but quite smooth, rather like an ocean liner's long flat sides and tapered ends.The Denali XL adds some of the upscale cues found on the Cadillac Escalade ESV, which shares the same basic structure.

The running board/side steps are integrated and unobtrusive, extending no farther than necessary, with a black grippy coating; powered retractable steps are available on some models.The tinted glass behind the C-pillar is expansive, and adds to both appearance and function.The front end has a clean appearance, with beefy block-like headlamps over a front bumper fascia.Doors close with a reassuring thud.

Wheels change visual perceptions of the Yukon XL.The standard aluminum wheel is a nice piece for look and function.You can add 20-inch wheels, some polished aluminum and others chrome-clad wheels that merely add a chrome-plated plastic cover to an existing wheel and could fall off or pack snow and muck depending on how you abuse your truck.Dealers offer a host of dress-up items, including wheels up to 22-inches.The standard 17-inch wheels offer the best ride quality due to tires with tall sidewalls.Ride quality gets harsher as wheel diameters go up.

The rear window opens separately, which is convenient for loading lighter bags and cargo.The larger liftgate is aluminum and balanced, upgradeable to power for those accustomed to a push-button world.Roof racks can carry unwieldly items that aren't too heavy, but be sure to load with the hatch open or after the cargo area is filled so the roof load doesn't interfere with the open hatch.

The instrument panel and center stack are elegant and worthy of a higher-end vehicle.The Denali model is richer still, with a wood and leather-wrapped steering wheel, nuance leather and darker wood trim than the other models.On all models the steering wheel is not perfectly ahead of the driver, something to consider if you frequent a chiropractor.

We found the touch-screen radio/navigation system easy to use, far easier to operate than Mercedes and BMW systems.We set the radio stations we liked and could quickly switch from favorite XM to AM to FM stations with the push of a single button; many vehicles require switching bands, then switching stations.The system has five groups of favorite stations for user assignment.While heading up the Interstate, the system warned of traffic incidents 19 miles ahead in our direction of travel.

The switchgear is simple, and the instrumentation is clean.The console is huge, with a deep storage box and a tray on top.The glovebox is large.Two cupholders are provided in a removable tray forward of the console and they work very well.There's another cupholder in each door pocket.A slot in the dash just left of the turn signal is perfect for coins or toll-road tickets.The pedals are adjustable, to accommodate short and tall drivers with the press of a button.

For reversing into tight confines, avoiding backing over a person, pet or play-toy, or easier trailer hitching, two rearview camera systems are offered.One is integral with the navigation system and the image appears on the navigation screen; the other shows the image on the inside-rearview mirror, so you get side-by-side near and far views to the rear.

The Yukon XL can seat six, seven, eight or nine passengers, depending on the seats selected.Our SLT had the second-row bucket seats, with room for seven, in a two/two/three configuration.

The second row offers good room, nearly matching the front.Second-row passengers in bucket seats have their own console, with an elbow tray, two cupholders each, audio controls and if equipped, the DVD screen overhead; the bench-seat second-row may be ordered with power releases to fold.With the touch of a button on the instrument panel or C-pillar, the seatbacks fold flat against the lower cushions, and then the seats flip up against the backs of the front seats.

The third row 50/50 seat has three seatbelts and two headrests.If you want to carry long items down one side the rear row becomes a one person seat; most vehicles with a third-row seat split it 60/40 so you can carry six people plus long pieces.The third-row seats fold easily but not flat into the floor like most of the competition; for a longer flat cargo floor the third row must be taken out (and these aren't light like baby seats) and left behind.

Head room in the third row is good, and leg room is okay (34.9 inches); the Expedition EL and Navigator L have a distinct advantage here because of their independent rear suspension.There is a great view through the wraparound glass, so it doesn't feel cramped or claustrophobic back there.Third-row climate control vents are inconveniently located in the headliner over the heads of the second-row passengers, but they can be aimed rearward toward the third-row passengers' knees.The second-row passengers have their own vents in the headliner, too, over their laps.

Cargo space is where the Yukon XL excels.There's 137.4 cubic feet of storage behind the front seats, with the second row folded and third row removed.Even with all seats in place, there's still 45.8 cubic feet of cargo space behind the third row.However, it's a nuisance to remove the third row for optimal storage space.The lift-over height at the rear bumper is relatively high, about the same as a pickup, so it's not easy to climb up into the cargo compartment to reach things, especially since there are no grab handles.

GM's trusty 5.3-liter Vortec V8 is the standard choice and it's a good one, making 310 horsepower and 335 pound-feet of torque; smooth and not too raucous, though not as torquey as the Expedition's 5.4 or Sequoia's new 5.7-liter V8 which nearly matches the optional 6.2's output.

The six-speed automatic transmission does its job well, completely in the background until you choose manual control or engage the tow/haul mode designed for heavy loads.We would choose the no-charge 3.42:1 axle ratio if we planned on anything more than lightly-loaded flat-terrain highway cruising.

If you need more power for towing with your 1500, the optional 395-hp 6.2-liter V8 boasts 417 pound-feet of torque, and the extra power comes with only a nominal dent in fuel economy.Any thoughts of economy with a big, heavy truck should be put aside.

If you have a trailer of 6500-7000 pounds or more and plan on towing with the Suburban full of gear and people, best to consider the 2500 XL.It has a heavy-duty 6.0-liter V8 with less horsepower and torque than the 6.2-liter but adds stronger axles and transmission, stouter steering, suspension and brake systems and truck-service wheels and tires.It is for all intents and purposes a three-quarter-ton pickup with a nine-seat body on top.Also noteworthy to travelers, the 2500-series has a much larger fuel tank (39 gallons versus 31.5 gallons in the standard Yukon XL 1500) so its effective range matches or betters the 1500.

You can also opt for the Denali, with its Corvette-related 6.2-liter engine making 403 hp and 417 pound-feet of stump-pulling twist.Denali tow ratings are the lowest in the XL line and there is no 4WD version for off-road use.

Active Fuel Management is standard on most engines.AFM shuts down four of the eight cylinders when they're not needed to save fuel.But at this size and weight all the cylinders are needed most of the time so the fuel saved is limited.A Yukon/Tahoe Hybrid or BMW X5, Audi Q7 or Mercedes GL350 diesel are the only three-row SUVs with decent fuel economy, and there is no hybrid Yukon XL though there is a hybrid Yukon.

Ride quality in the Yukon XL is excellent, overall.Even when the optional 20-inch wheels are chosen, the suspension deals deftly with road imperfections and potholes but you feel them more.We prefer taller tires on our trucks, however, for ride comfort, impact resistance and in some respects, better performance.

The Yukon XL is very stable at highway speeds, though it wallows a bit on undulating freeways.Autoride, the rear self-leveling and active suspension, electronically adjusts to the road as read by sensors.It reduces body lean in corners, enhances stability on rough roads, and reduces nose-dive under hard braking.Autoride is optional on Yukon XL, standard on Denali.

The rack-and-pinion steering on the 1500 models feels fairly direct, though as in other big SUVs it is a bit slow.The 2500 steers like a new pickup, a bit heavier but confidence-inspiring.Like all large SUVs, the Yukon XL is prone to body lean in turns and doesn't respond well to quick changes of direction.It's a full-size truck (think three tons, higher center of gravity) and needs to be driven accordingly and with respect for others, not like it's a sports car.

Hard crosswinds tend to blow big SUVs around and the Yukon XL is no exception.Driving in a 25-mph crosswind on the freeway at 75 miles per hour, our Yukon XL swayed considerably because of its billboard-like profile.Tire choice affects this behavior.Autoride helps reduce the effect of crosswinds.And 2500 models better withstand crosswinds.

The brakes are all vented discs with ABS, and perhaps the biggest improvement in this generation Yukon.An integrated trailer brake controller that gives excellent control and eliminates any installation hassles is available, and we view it as a must-have option.

NewCarTestDrive.com correspondent G.R.Whale reported from Los Angeles, with Sam Moses in Portland, Kirk Bell in Chicago.