the Navigator's previous platform, this platform provided greater rigidity for better driving dynamics. The independent rear suspension was replaced with a five-link IRS design to improve handling and ride quality. The Navigator continued to come with standard 18-inch alloy wheels, but both 20- and 22-inch wheels became available. The 5.4 L 3-valve SOHC V8 introduced in the 2005 Navigator remained unchanged for 2007. The ZF Friedrichshafen 6-speed automatic transmission was replaced by Ford's own 6-speed design, the 6R80 for the 2009 model year. Due to the Navigator's redesign, its base curb weight increased to in two-wheel drive models and in four-wheel drive models. Navigator L models were even heavier, at in two-wheel drive models and in four-wheel drive models. In spite of this, thanks to an improved frame, the Navigator's towing capacity increased for 2007, approaching in two-wheel drive models. After the 2007 model redesign, the Navigator no longer used the same transfer case as the Expedition. Expedition four-wheel drives continued to use a two-speed dual range transfer case with off-road low range reduction gearing and default off-road program that remaps (reprograms) the electronic throttle control and traction control system response for off-road conditions. Navigator four-wheel drives were demoted to a light-duty one-speed single range transfer case which lacks low-range gearing. For 2008, packaging for the Navigator's luxury and convenience features was simplified, resulting in the elimination of the Luxury and Ultimate trim levels and the standardization of a number of features that were previously optional. Some of these newly standard features included heated and cooled front seats, power-folding third row seats, a power liftgate, and a 600-watt 14-speaker THX II-Certified audio system. Also newly standard was a 3.31:1 rear axle ratio, though a 3.73:1 ratio was still available as option for the Navigator and remained standard in the Navigator L. Newly available was a rearview camera to aid in backing up. For 2009, the Navigator's 5.4 L V8 gained as well as flex-fuel capability. The rearview camera that was new for 2008 was now standard, as were heated second row seats, Front Park Assist, a capless fuel filler, rain-sensing windshield wipers, and Lincoln SYNC. The third generation Navigator and Navigator L continued to be offered for the 2010 model year, with only slight changes. For 2011, both the Navigator and the Navigator L featured HD Radio, Sirius TravelLink, and Lincoln SYNC as standard on all trims. The optional 20-inch