Wikipedia
R.T. Quaife Engineering, Ltd. is a British manufacturer of automotive drivetrain products. It designs and manufactures replacement gearboxes and gear sets, some of which are for four-wheel drive systems.
Quaife's signature product is its line of automatic torque biasing differentials, a form of limited slip differentials that employ helical gears rather than clutch mechanisms that are controlled either mechanically or by computers. These differentials are usually available as aftermarket items, but for some models are specified by automobile manufacturers as OEM equipment.
Quaife has also briefly built complete road cars, with the R4 GTS in 1999 which also competed in the British GT Championship. The company has also produced the R40, a roadster with a rear mounted V8 bike engine mated to one of the company's transaxle gearboxes. The 40 relates to the 40 valves the engine has.
The company was founded in 1965 by Rod Quaife and now run and owned by Michael Quaife (Technical Director) and his sister Sharon Quaife-Hobbs (Financial Director). Michael's son, Phil Quaife and Sharon's son Adrian Quaife-Hobbs are both professional racing drivers.
Aside from manufacturing popular, well built differentials, Quaife also manufactures solid, highly sought after, reliable sequential gearboxes (such as the QBE60G, and QBE69G) offered in several bell housings to fit several popular racing chassis. Based near Sevenoaks, Kent they have two sites, one in Sevenoaks and the other, their OEM production facility, in Gillingham. Prior to 2013 US customers were able to place orders directly through Quaife, however in early 2013 a contract was signed with Motovicity (32655 Industrial Dr. Madison Heights, MI. USA 48071) for sole distribution in the United States.
In the Fall of 2012 the company acquired the company Tran-X, and continues to serve its customers.