Looking at '15s, both Tahoes and Yukon SLTs. The Yukon offers a two-speed transfer case on the SLT and Denali when ordered with AWD and the trailering package. It's a rotary dial to the left of the steering wheel that lets you select auto awd, 2wd or 4wd hi and 4wd low.... I like this feature, but I can't tell if it is available on the Chevy?