The ZF S6-650 is a 6-speed

manual transmission A manual transmission (MT), also known as manual gearbox, standard transmission (in Canadian English, Canada, British English, the United Kingdom and American English, the United States), or stick shift (in the United States), is a multi-speed ...

manufactured by

ZF Friedrichshafen AG ZF Friedrichshafen AG, also known as ZF Group, originally ''Zahnradfabrik Friedrichshafen'' (), and commonly abbreviated to ZF, is a Germany, German technology manufacturing company that supplies systems for passenger cars, commercial vehicles ...

. It is designed for

longitudinal engine In automotive engineering, a longitudinal engine is an internal combustion engine in which the crankshaft is oriented along the long axis of the vehicle, from front to back. See also: transverse engine Use This type of motor is usually used fo ...

applications, and is rated to handle up to of

torque In physics and mechanics, torque is the rotational analogue of linear force. It is also referred to as the moment of force (also abbreviated to moment). The symbol for torque is typically \boldsymbol\tau, the lowercase Greek letter ''tau''. Wh ...

General Motors General Motors Company (GM) is an American Multinational corporation, multinational Automotive industry, automotive manufacturing company headquartered in Detroit, Michigan, United States. The company is most known for owning and manufacturing f ...

used the S6 as RPO ML6. Gear ratios:

Applications

* 2001–2006

Chevrolet Silverado The Chevrolet Silverado is a range of trucks manufactured by General Motors under the Chevrolet brand. Introduced for the 1999 model year, the Silverado is the successor to the long-running Chevrolet C/K model line. Taking its name from the to ...

2500HD and 3500 * 2001–2006

GMC Sierra The Chevrolet Silverado is a range of trucks manufactured by General Motors under the Chevrolet brand. Introduced for the 1999 model year, the Silverado is the successor to the long-running Chevrolet C/K model line. Taking its name from the t ...

2500HD and 3500 * 1999–2010

Ford Super Duty The Ford Super Duty (also known as the Ford F-Series Super Duty) is a series of heavy-duty pickup trucks produced by the Ford Motor Company since the 1999 model year. Slotted above the consumer-oriented Ford F-150, the Super Duty trucks are an e ...

F-250, F-350, F-450 & F-550 (with diesel engines) * 2002–2010

F-250, F-350, F-450 & F-550 (with gas engines)

Bellhousing variants

* 7.3 Powerstroke (same as 7.3/6.9 IDI bellhousing) * 6.0 Powerstroke (larger bellhousing than automatic variant) * 6.4 Powerstroke ( ZF S6-750) * 5.4/6.8 Triton (same bellhousing as automatic 6.0/6.4 Powerstroke) * 6.6 Duramax * 8.1 Vortec V8

Significance

ZF introduced the S6-650 in 1998 on the Ford Super Duty. GM started using the ZF S6-650 in 2001 with some alterations, making this transmission different from the Ford version. The S6-650 will likely be the last

GM and

Ford Ford commonly refers to: * Ford Motor Company, an automobile manufacturer founded by Henry Ford * Ford (crossing), a shallow crossing on a river Ford may also refer to: Ford Motor Company * Henry Ford, founder of the Ford Motor Company * Ford F ...

will use in their heavy pick ups, due to advancements in

automatic transmission An automatic transmission (AT) or automatic gearbox is a multi-speed transmission (mechanics), transmission used in motor vehicles that does not require any input from the driver to change forward gears under normal driving conditions. The 1904 ...

technology and low consumer demand for manual transmissions. However, Ford did offer the Tremec TR-4050 transmission until 2019.

Issues

The gasoline version of the ZF6 and ZF5 is known to have poor casting issues, especially around the transmission mounts. This can lead to the mounting ears breaking off. Other issues include the older version of the shift fork not being as strong as the updated variant.

Construction

The ZF S6-650 – Heavy Duty 6 speed manual transmission has an aluminium alloy main gear case and tail housing with the bell housing integral to the case. It is built in two-wheel drive and four-wheel drive versions. The model used in the Ford trucks has an internal oil pump to circulate and cool the lubricant, which is uncommon in manual transmissions. The GM versions are not equipped with an oil pump. All gears are synchronized. There is a dual cone synchronizer on 2nd and 3rd gears with an input torque rating of .

References

* http://www.autoworld.com/news/gmc/zf_s6_650.htm S6-650 General Motors transmissions {{automotive-part-stub