Once the most important part of the automakers lineup, the big SUV is now in danger of becoming irrelevant.
The market for big SUVs is not what it once was. Part of this is simply due to the trend for buying them is coming to an end, but part of it has also been the huge increases in gas prices in the years since the big vehicles started to become popular. Now the competition has become all the more fierce between manufacturers that still wish to hold on to a part of this market. So improving fuel economy has become important for both CAFE rules and for staying competitive.
To this end, GM is looking to the powertrains in big SUVs in the hopes of finding ways to keep them viable. Specifically, this means the Escalade, Tahoe, Suburban and Yukon, all of which share a platform. The first step will be new transmissions, which GM already has in the works, including a new 8-speed and a 10-speed transmission. GM is also apparently looking into hybrid options, even though the Escalade hybrid has already proven to be a sales dud. Diesels are also being considered, but as yet, GM hasn't actually committed to anything other than the transmissions.