Availability of a navigation system leads 2005 updates to this transformer pickup. Avalanche is basically a Chevrolet Suburban SUV with an open cargo bed separated from the cab by a midgate. Lowering the midgate and rear seat extends the 5.3-ft cargo box to 8.1 ft. The rear window also removes and stores onboard. Avalanche comes as a half-ton 1500 model with 5.3-liter V8 and as a heavy-duty 2500 with 8.1-liter V8. The 1500 offers rear-wheel drive with optional traction control. Optional on 1500s and standard on 2500s is GMs Autotrac 4WD that can be left engaged on dry pavement and includes low-range gearing. All models have automatic transmission, antilock 4-wheel disc brakes, standard seating for six, and a tire-pressure monitor. Front side airbags and OnStar assistance are available. New 05 options include an integrated audio/navigation system with touch screen, and a chrome package with LS trim. Optional satellite radio and rear DVD entertainment continue.