America's top-selling sport-utility vehicle was redesigned as an early 2002 model, placed on sale in spring 2001. Ranking as a midsize model, the Explorer retained its body-on-frame construction, but gained new styling, a wider stance, longer wheelbase, and an independent rear suspension. A newly available third-row seat permitted seven-passenger capacity. Mercury's upscale Mountaineer was similarly revamped, but with more differentiated styling. Explorers and Mountaineers were among the few midsize SUVs with an independent rear suspension. Explorers came with a V6 or V8 engine. The V6 teamed with either a manual or automatic transmission, while the V8 was offered only with a five-speed automatic. Explorers could have either rear-wheel drive or Ford's Control Trac four-wheel drive, which could be left engaged on dry pavement and included low-range gearing. Antilock all-disc brakes were standard. Torso side airbags were not available, but curtain side airbags were optional. Later in the model year, Ford offered sensors that could deploy the curtain airbags in a rollover accident. Ford's Advance Trac antiskid system also became available later. Top-level Eddie Bauer and Limited models included a driver's seat memory, tilt/telescopic steering wheel, and power-adjustable pedals. A rear-obstacle warning system was optional. Ford continued to use the Explorer's 1995-2001 vintage design for the Explorer Sport two-door wagon and the Sport Trac four-door crew cab.