The 2018 GMC Yukon XL is available as a 4-door, 7-seat sport utility. Starting at $51,800, the 2018 GMC Yukon XL SLE 4x2 is powered by a 5.3L , 8 -cylinder engine mated to an automatic transmission that returns an EPA estimated 16-mpg in the city and 23-mpg on the highway. The top of the line 2018GMCYukon XLSLT Standard Edition 4x4 , priced at $ 60,100 , is powered by a 5.3L , 8 - cylinder engine mated to an automatic transmission that returns an EPA estimated 15-mpg in the city and 22-mpg on the highway.