This crossover SUV/pickup truck is based on the Chevrolet Suburban and uses General Motors' innovative "midgate." Avalanche has four full-size side doors and an open cargo bed separated by the midgate. The rear seat folds and the midgate lowers to eliminate the barrier between cabin and bed, converting the 5.3-ft cargo box to 8.1 ft. The rear window detaches and stores onboard, the bed sidewalls have storage compartments, and the tailgate locks. Standard seating is for six. Front buckets are available. Leather upholstery, heated front buckets, and a power sunroof are optional. The half-ton-payload Avalanche 1500 uses a 5.3-liter V8. The heavy-duty 2500 models have an 8.1-liter V8 and a 37.5-gal fuel tank, 6.5 gal more than the 1500. Both have automatic transmission, front side airbags, and antilock 4-wheel disc brakes. Avalanche offers rear-wheel drive with optional traction control, or GM's Autotrac 4WD that can be left engaged on dry pavement and includes low-range gearing. GM's OnStar assistance system is optional. The 2WD 1500s offer rear self-leveling and a Z66 on-road suspension package, the 4x4s a Z71 off-road suspension. The 1500s also offer "North Face" trim created with the clothing/equipment maker.