ZF 8HP transmission

Updated on Nov 27, 2024

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Manufacturer ZF Friedrichshafen Predecessor ZF 6HP transmission		Production 2008–

Class 8-speed longitudinal automatic transmission

The ZF 8HP is an eight-speed automatic transmission designed and built by ZF Friedrichshafen. It had its debut in the new BMW 7 Series (F01) 760Li saloon fitted with the V12 engine, and since then each new BMW model in all Series down to the 1 Series in rear-wheel-drive and all-wheel-drive versions have been equipped with it.

One of its main aims is to improve vehicle fuel economy, and it can achieve an 11% saving compared to the ZF 6-speed transmission and 14% versus modern 5-speed transmissions. Due to changes in internal design, the shift times have reduced to 200 milliseconds; additionally, the unit brings the ability to shift in a non-sequential manner - going from gear 8 to gear 2 in extreme situations. In the 8HP70 version, it has a torque handling limit of 700 newton metres (516 lbf·ft), and weighs 87 kilograms (192 lb).

Future development will see two four-wheel drive versions available, with a version destined for Volkswagen Group applications using a Torsen centre differential. It will be able to encompass a torque range from 300 newton metres (221 lbf·ft) to 1,000 newton metres (738 lbf·ft), and will be available for use in middle-class cars through to large luxury sport utility vehicles.

Chrysler Group LLC initially received the 8HP 8-speed automatic transmissions from the ZF plant in Saarbrucken, Germany. By 2013, in parallel with Chrysler Group, ZF had set up a new transmission production plant in Gray Court, South Carolina. ZF Friedrichshafen and Chrysler Group have reached a supply and license agreement for the 8HP. Chrysler Group is licensed to produce the 8HP at the company’s Kokomo Transmission Plant and the Kokomo Casting plant, production began in 2013.

2nd generation 8HP products were released starting in 2014. Efficiency improvements over the original design include a wider ratio spread of 7.8:1, reduced drag torque from the shift elements, reduction in required oil pump pressure, and broadened use of the coasting and start-stop systems. ZF estimated fuel economy improvement over 1st generation 8HP kits to be 3%. Refinements were also made with respect to vibration.

Gear ratios

Below is a table of reference gear ratios as provided with the ZF 8HP transmission, though actual implementations may differ depending on the tuning and specifications of individual vehicle manufacturers such as Mercedes Benz, BMW and Audi. Differences in gear ratios have a measurable, direct impact on vehicle dynamics, performance, waste emissions as well as gas mileage.