GMC Sierra III (GMT900) photos

Debuting in late 2006 for the 2007 model year, the third-generation GMC Sierra utilized General Motors' GMT900 platform, emphasizing improved aerodynamic efficiency, a steeper windshield rake, tighter panel gaps, and a strengthened hydroformed boxed frame. Light-duty models adopted coil-over-shock front suspension and rack-and-pinion steering to enhance handling precision. Available in Regular Cab, Extended Cab, and Crew Cab configurations, the Sierra offered two distinct interior layouts: a standard functional dashboard and a premium luxury-oriented layout shared with GMC full-size SUVs. Engine offerings spanned the 4.3-liter V6, 4.8-liter, 5.3-liter, and 6.0-liter Vortec Gen IV V8 engines featuring Active Fuel Management cylinder deactivation, plus a 6.2-liter V8 exclusive to the Denali trim. Heavy-duty 2500HD and 3500HD trucks featured high-output Duramax 6.6-liter diesel engines mated to Allison transmissions. Transmission choices evolved from four-speed automatics to the 6L80 six-speed automatic gearbox. From 2009 to 2013, an advanced Two-Mode Hybrid variant combined a 6.0-liter V8 with dual electric motors. This generation achieved notable commercial success across North America and select export markets.