From GM press: The Yukon and Yukon XL family of full-size SUVs continues to offer performance, capability and segment-leading fuel economy. Yukon Denali models are distinguished with unique exterior design cues, including a signature honeycomb chrome grille. Denali-exclusive headlamps and taillamps further the jeweled look of these special Yukon models.
Changes for 2010 that enhance the lineup’s efficiency include variable valve timing on models with the 5.3L engine, as well as Active Fuel Management and a “taller” 3.08 axle ratio on Denali models. Additionally, FlexFuel capability is added to the 5.3L engines.
The Yukon XFE model that was introduced during the 2009 model year returns, offering 21 mpg on the highway. Additional product changes include two new exterior colors, USB ports on the radios and a standard single-speed transfer case on 4WD models. (A two-speed transfer case is optional).