The GMC Yukon XL is a long-wheelbase version of the Yukon, just as the Chevrolet Suburban is a long wheelbase version of the Tahoe. XL means extra long; the Yukon XL is based on the same platform as the Yukon, but it's stretched 14 inches in wheelbase and about 20 inches overall. While the Yukon can carry a lot of people or a lot of cargo, the Yukon XL can do both at the same time. The Yukon XL also offers a bigger towing capacity. (Look for a separate NewCarTestDrive.com review of the standard-wheelbase GMC Yukon and Yukon Denali.)
GMC offers the Yukon XL with two-wheel drive or four-wheel drive. It comes in two load ratings: The popular 1500 model is rated to tow trailers up to 8800 pounds with 2WD, or 8600 pounds with 4WD. The heavy-duty 2500 is rated to pull trailers up to 12,000 pounds in 2WD or 4WD. (Unless you're pulling heavy trailers, you'll want the 1500 model for its smoother ride quality.)
Each of these variations is available in two trim levels, the already well-equipped SLE and even better-equipped SLT.
Yukon XL Denali adds a bigger engine and a sophisticated full-time all-wheel-drive system to the Yukon XL. Denali also comes standard with nearly every option offered on the regular Yukon XL models. A distinctive grille, wheels, body cladding, and interior trim distinguish the Denali from the rest of the Yukon XL line.
All Yukon XL 1500 models in SLE or SLT trim come with a 285-horsepower 5.3-liter Vortec V8. Yukon XL Denali comes only with a 320-horsepower 6.0-liter Vortec V8. 2500 models offer a choice of the 6.0-liter V8, or a monster 340-horsepower 8.1-liter big-block Vortec V8.
All models come with an electronically controlled four-speed automatic transmission.
Yukon XL 4WD models use a fairly conventional part-time system GM calls Autotrac; it uses a two-speed transfer case that locks front and rear axle speeds together in four-wheel-drive mode. This is the traditional kind of four-wheel drive that is considered best for serious off-road driving. Pressing a button switches the system to an Auto 4WD mode that automatically shifts torque between the front and rear wheels as conditions demand. A locking rear differential is optional.
Denali comes with a more sophisticated full-time all-wheel-drive system that uses a planetary center differential set for a 38/62 front/rear torque split; a silicone viscous coupling unit progressively locks up if one axle or the other starts to slip. This is all contained in a cast-magnesium housing that saves 15 pounds compared to the standard 4WD system. Aluminum front and rear prop shafts save even more weight and minimize vibration. A locking rear differential is standard on the Denali.
Prices start at $36,157 for the 1500 and $37,529 for the 2500. Add about $2600 for 4WD. Two different SLT packages are offered, one adding $2105, and the other $3273, to the cost of an SLE. Denali is priced at $48,050, but includes every possible option except an engine-block heater ($35), power sunroof ($1000), and second-row bucket seats ($490).