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Overview
The GMC Sierra All Terrain HD concept is an exploration of heavy-duty truck capability combined with greater off-road versatility. It is highlighted by a bold exterior design, enhanced all-terrain ...

Under the Hood
GM's two-mode hybrid system enables "full" hybrid operation with the capability to cruise on electric power up to 30 mph. The gas engine kicks in if more acceleration is needed, as well ...

Seat Issues
As I say, I liked the look of the leather seats. Once I started driving, though, they offered no support in any direction; I felt like I was sitting on top of the seat rather than in it. While it' ...