GMC offers the Yukon XL with rear or four-wheel drive, and 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 heavier-duty 2500 is rated to pull trailers up to 12,000 pounds in 2WD or 4WD. Each of these variations is available in two trim levels, the already well-equipped SLE and even better equipped SLT.

New for 2001 is the luxurious Yukon XL Denali. (GMC has offered a Denali version of the shorter Yukon since 1998.) Based on the 4WD Yukon XL 1500, the Yukon XL Denali packs a bigger engine and more sophisticated full-time all-wheel-drive, and makes standard nearly every option offered on the regular Yukon XL models. Distinctive grille, wheels, body cladding, and interior trim distinguish the Denali from the rest of the Yukon XL line.

All Yukon XL 1500s 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. 2500s offer a choice of the 6.0-liter V8, or a new-for-2001 340-horsepower 8.1-liter Vortec big-bock V8.

Regardless of engine, all XL models come with an electronically controlled four-speed automatic transmission.

SLE/SLT Yukon XLs with 4WD 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.

Denali comes with a more sophisticated full-time all-wheel-drive system from supplier New Venture Gear 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 Autotrac. Aluminum front and rear prop shafts save even more weight and minimize vibration. A locking rear differential, optional on other Yukon XLs, is standard on Denali.

Prices start at $35,552 for the 1500 and $36,924 for the 2500; add $2400-$2500 for 4WD. Two different SLT packages are offered, one adding $2050, and the other $2968, to the cost of an SLE. Denali is priced at $47,450, but that figure includes every possible option except an engine-block heater, power sunroof, and second-row bucket seats.