The ZF6 is a heavy-duty, fully synchronized, constant-mesh 6-speed manual transmission

Manual transmission

A manual transmission, also known as a manual gearbox or standard transmission is a type of transmission used in motor vehicle applications...

.

There are a few variances of the ZF6

Ford

Ford Motor Company

Ford Motor Company is an American multinational automaker based in Dearborn, Michigan, a suburb of Detroit. The automaker was founded by Henry Ford and incorporated on June 16, 1903. In addition to the Ford and Lincoln brands, Ford also owns a small stake in Mazda in Japan and Aston Martin in the UK...

 has been using the ZF6 since the late 1990s. Ford's configuration uses a unique internal oil pump

Oil pump (internal combustion engine)

The oil pump in an internal combustion engine circulates engine oil under pressure to the rotating bearings, the sliding pistons and the camshaft of the engine...

 to pump lubricating oil to an external oil cooler, much like that of an automatic transmission

Automatic transmission

An automatic transmission is one type of motor vehicle transmission that can automatically change gear ratios as the vehicle moves, freeing the driver from having to shift gears manually...

, to dissipate the heat generated during heavy-duty use or towing. It also uses a different input bearing. The Ford ZF5 and ZF6 line uses a tapered input bearing for added strength.

General Motors

General Motors

General Motors Company , commonly known as GM, formerly incorporated as General Motors Corporation, is an American multinational automotive corporation headquartered in Detroit, Michigan and the world's second-largest automaker in 2010...

 used the ZF6 transmission in the 1989-1996 Corvette

Chevrolet Corvette

The Chevrolet Corvette is a sports car by the Chevrolet division of General Motors that has been produced in six generations. The first model, a convertible, was designed by Harley Earl and introduced at the GM Motorama in 1953 as a concept show car. Myron Scott is credited for naming the car after...

 (Model Number ZF S6-40). They started using them again in 2001 mated to their 8100 Vortec and the Isuzu Duramax (Model Number ZF S6-650) engines. GM modified theirs to accommodate for the complaints Ford had with theirs. A large complaint was the noise produced. They added a bushing

Bushing (isolator)

A bushing or rubber bushing is a type of vibration isolator. It provides an interface between two parts, damping the energy transmitted through the bushing. A common application is in vehicle suspension systems, where a bushing made of rubber separates the faces of two metal objects while allowing...

 to metal rail socket for the shifter stub. They gave the shifter a "longer" throw for a more firm feel. They also added more angle to the helical gearsets to aid in reducing noise. GM models do not use an external oil cooler. Instead, they opted for allowing the transmission to operate at a higher temperature, then specified the use of synthetic oil

Synthetic oil

Synthetic oil is a lubricant consisting of chemical compounds that are artificially made . Synthetic lubricants can be manufactured using chemically modified petroleum components rather than whole crude oil, but can also be synthesized from other raw materials...

, which will tolerate higher temperatures than conventional oil and is expected to last the life of the vehicle without oil changes.

Fluid Specifications:

• Ford Diesel/Gas - 5.8 Quarts (refill capacity) of Mercon V or XT-M5-QS (Motorcraft Full Synthetic Manual Transmission fluid.) (check owners manual for proper fluid type).
• Corvette - 2.2 Quarts of 5w-30 Motor Oil (Use only GM 1052931 or Pennzoil Synchromesh)
• GM Trucks -