In 1870, at a time when the weaving industry was flourishing in Coventry, William Riley Jr. became a master weaver in his family's business, which also produced weaving machinery for sale to other businesses, an activity which provided him with a sound engineering knowledge.

The weaving industry, however, soon entered a period of rapid decline, forcing William Riley to seek more profitable ventures, and in 1890 he and his associates acquired the Bonnick Cycle Co., which they re-named the Riley Cycle Co. Ltd. six years later.

At first, the small engines fitted to Riley Cycles were obtained from specialist engine manufacturers, but the desire to design and produce their own engines was strong, and in 1902 the Riley Engine Co. was established by three of William's sons Victor, Percy and Allan. They patented the mechanically operated inlet valve. Head of the new company was William Riley's son Percy, who at the age of 20 was already a practical and ingenious engineer who had successfully built his first car before his 18th birthday.

Having outgrown its original site, the Riley Engine Co. moved in 1906 into new premises in Aldbourne Road, which it and its successors were to occupy continuously until 1974. 

In 1907 they announced the first ever detachable road wheel, designed by Percy. These wheels became an important part of the company's business as demand became worldwide, 183 manufacturers paid to use the patent rights. 

The focus of interest moved from motor cycles to motor cars, and in 1912/13 the Riley Motor Manufacturing Co. also transferred to Aldbourne Road.

The heyday of the Riley  marque was the inter-war period when a whole series of brilliant models where produced, of which the Riley 9, which made its first appearance in 1926, was perhaps the most famous.  The engines and gearboxes for these cars where all produced by the Riley Engine Co. in Aldbourne Road.

When the Riley car business was taken over by the Nuffield Organisation, Percy Riley and his associates retained control of the Riley Engine Co., and subsequently re-named it P.R. Motors Ltd.

The original intention was to produce a small car, but the outbreak of war, followed in 1941 by Percy Riley's untimely death, put an end to this project and by 1946 the factory was firmly committed to the manufacture of gears and transmissions.

At first, P.R. Motors was best known as a supplier to the motor industry but in the early 50's the company took an entirely new and significant course with the introduction of its first dumper transmission, a "crash" gearbox with fabricated gearcase providing two forward speeds and one reverse, and employing a flat belt as a clutch.  An improved version with a cast iron case was introduced later.

Several thousands of these gearboxes were produced, but it became evident that the sliding gears were having a hard time at the hands of strong-armed dumper drivers, and this led to the design of the first in a series of heavy duty gearboxes with constant mesh gears.  This was the CM, which first appeared in 1955, and , with modifications, continued in production for some 20 years.

Demand for the new products increased, and in 1964 the No. 2 factory in Earlsdon was acquired.  Eventually, the Riley family severed its connection with the company in 1966 when it was acquired by the Charterhouse Group through its subsidiary, Newage Engineers Ltd., and then, in 1971 P.R. Motors became the Transmissions Division of Newage Engineers.

As the company continued to prosper, and to cater for the increased demand for its existing products and its projected expansion into related transmissions products, a new factory was purpose-built at Barlow Road in 1974.

The company built a very close partnership with its customer base which led to the company being the preferred source of drive axles and gearboxes for the British dumper industry.  As well as other vehicles produced in the U.K., France, Germany, Switzerland, Austria and other countries. This has resulted in a steady stream of new and improved transmissions, both standard products such as 40M and 85M gearboxes, as well as dedicated products to meet specific customer requirements.

This close relationship with the dumper industry led Newage to acquire Gear Drive Systems in 1975 and develop a full range of double reduction axles with totally enclosed oil immersed brakes specifically for their needs, although the range was later broadened to general off-highway applications. The same criteria for reliability for which the company's gearboxes are so well known was applied to the range of axles.

In 1980 the divisional structure was disbanded with P.R. Motors re-acquiring the business of the Transmissions Division from Newage Engineers and being renamed Newage Transmissions Limited.  In the same year Gear Drive Systems transferred to the Coventry Site from Irvine, Scotland.

In July 1985 the five executive directors of Newage Transmissions Limited arranged their own management buyout.  In September 1986 the company was quoted on the Unlisted Securities Market and became a Plc.

The combination of design, manufacturing and customer application knowledge resulted in the successful  range of gearboxes which, supported by high customer service levels, rapidly led to domination of this market sector.

In September 1988 Newage Transmissions Plc was acquired by Williams Holdings Plc. leading to a major investment programme to increase the capacity of the company with Brockhouse Transmissions being acquired in 1991 to increase the product range.

Following a management buyout of the engineering division of Williams Holdings Plc, Newage Transmissions Ltd became part of Cortworth Plc in 1993.

An uprated range of PRM marine gearboxes was launched in 1997 with the introduction of its first mechanical gearbox the PRM120 .

During 1997 B.I. Group Plc acquired the Cortworth Plc group including Newage Transmissions Ltd.

The marine gearbox range was expanded with the launch of the PRM80 and PRM1500 in 1999.

Newage showed its continued commitment to product development by re-designing its range of off-highway rigid drive axles in 2001. The new range has a compact modular design providing simplified axle installation, good accessibility and optimum ground clearance, with a new increased range of options and also extending the range to cover vehicles with a payload up to 10 tonnes.

In June 2005 Newage was acquired by Thornycroft (1862) Limited, who went into administration in September 2006. The Company was subsequently acquired by Commatech Holdings in October 2006.