What is Transfer case?
[[File:Automotive diagrams 02B En.png|thumb|right|250px|{{Center|Shown is the transfer case and driveshafts}}]] A '''transfer case''' is a part of the [[drivetrain]] of [[four-wheel drive]], [[all-wheel drive]], and other multiple powered [[axle]] vehicles. Typically a transfer case is used to [[wikt:engage|engage]] (and disengage) the four-wheel drive function.<ref>{{cite web |url=http://www.fourwheeler.com/how-to/68958-how-transfer-cases-work/|title=How Transfer Cases Work|author=Drew Hardin|date=1 March 2002 |publisher=Fourwheeler Network |access-date=27 August 2015}}</ref> When disengaged, most four-wheel drive systems operate in two wheel drive (engaging just the rear axle and wheels). For that reason [[two-wheel drive]] vehicles do not need a transfer case. The transfer case transfers the power from the [[transmission (mechanics)|transmission]] to the front and rear [[axle]]s by means of [[drive shaft]]s.<ref name=RichBB>{{cite web|url=http://bb4wa.com/simply-put-4x4-transfer-case/|title=“Simply Put” 4×4 Transfer Case|author=Dan Rich|publisher=Bill Burke's 4-Wheeling America|access-date=27 August 2015|archive-date=5 September 2015|archive-url=https://web.archive.org/web/20150905105110/http://bb4wa.com/simply-put-4x4-transfer-case/|url-status=dead}}</ref> The transfer case [[wikt:synchronizes|synchronizes]] the rotation of the front and rear wheels so they turn at exactly the same speed. It usually contains two or more sets of gears. It has a 1:1 [[ratio]] drive (usually called high range) for normal city and highway use. Then it contains a low range gear for [[wikt:off-road|off-road]] use. A common low range gear ratios is 2.72:1. That means for every 2.72 rotations of the transmission output shaft, the transfer case will turn both driveshafts 1 rotation. The [[Jeep Wrangler]] Rubicon model uses a 4:1 low range gearing. ==Drive types== There are two different types of internal power-transfer mechanism found in most transfer cases. ===Gear-driven=== [[Gear]]-driven transfer cases use sets of gears to tra