GMC has released partial pricing for the 2027 Sierra HD, and the headline number is a six-figure sticker. The Denali Ultimate Crew Cab 4WDnow lists at $99,395, up $2,400 over 2026. But the most expensive configuration is the off-road AT4X: add the new diesel and it runs $100,595 with destination.What's priced so farFor now, pricing covers only the 2027 Sierra 2500 HD Crew Cab with four-wheel drive. GMC hasn't yet announced numbers for rear-wheel-drive trucks, single and double cabs, or the 3500 HD. Most trims see a flat $900 increase. The Pro starts at $57,495, the SLE at $61,895, the SLT at $69,195, the AT4 at $76,195, the Denali at $78,895, and the AT4X at $89,195 before options. The Denali Ultimate is the exception with its $2,400 bump. Every trim below the Denali Ultimate ships with the 6.6-liter gas V8 standard. On the Denali Ultimate, the new 8.3-liter V8 turbodiesel Duramax is standard; elsewhere it's an $11,400 add-on. That option is what pushes the AT4X past $100K.New powertrains and chassis bitsThe updated 6.6L V8 now produces 412 horsepower and 472 lb-ft of torque, which GMC calls class-leading. The 8.3L Duramax turbodiesel puts down 555 hp and 1,230 lb-ft, both figures GMC says beat Ford's high-output Power Stroke. With the diesel, the Sierra HD tows up to 38,000 lbs. Backing that up are bigger 14.6-inch front brake rotors and a recalibrated Tow/Haul mode. A segment-first rack-and-pinion electric power steering setup replaces the old system, improving control on- and off-road. The AT4X - the range's top off-road trim - gets upgraded DSSV dampers plus a Terrain Mode exclusive to the trim. Inside, expect the same 13.4-inch touchscreen. The Denali Ultimate adds wood trim, massaging power front seats, leather, a Bose system, and illuminated power assist steps.Where it landsFor comparison, the 2027 Ford F-250 XL Crew Cab 4x4 starts at $55,935, slightly undercutting the base Sierra. The gap widens up top: the F-250 Platinum 4x4 runs $82,410. This is not a full redesign. The 2027 Sierra HD goes on sale late in 2026.