The 2006 GMC Yukon is available as a 4-door, 5-seat sport utility. Starting at $36,305, the 2006 GMC Yukon SLE 4x2 is powered by a 4.8L, 8-cylinder engine mated to an automatic transmission that returns an EPA estimated 16-mpg in the city and 20-mpg on the highway. The top of the line 2006 GMC Yukon Commercial Fleet 4x4, priced at $39,805, 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 19-mpg on the highway.