Here is a Detailed View of ZF’s 8HP Automatic Transmission

Here is a Detailed View of ZF’s 8HP Automatic Transmission 8 photos
Photo: ZF Friedrichshafen AG
ZF 8HP TransmissionBMW 7 SeriesAlfa Romeo Giulia QuadrifoglioJeep Grand Cherokee SRT TrackhawkLamborghini UrusAudi RS6ZF 8HP Transmission - 4th Generation
The German gearbox supplier revealed the eight-speed automatic transmission in 2008, when it debuted on the F01 BMW 7 Series. Since then, it has become arguably the best automatic transmission out there, evolving into multiple versions and spawning into three generations, with the fourth set to be released soon.
ZF Friedrichshafen AG's trademark name for this transmission is 8HP, which is an acronym for 8-speed transmission with Hydraulic converter and Planetary gearsets.

It debuted in 2008 on the BMW 7 Series 760Li sedan that featured the mighty V12 engine. Since then, all new BMW models with rear or all-wheel-drive can be equipped with this transmission and updated versions are used by many manufacturers such as Volkswagen, Audi, Bentley, Rolls-Royce, Aston Martin, Dodge or Lamborghini.

Its revolutionary design revealed an entirely new gear set concept with four gearsets that require only five shift elements, of which only two are open in any given gear.

ZF 8HP Transmission
Photo: ZF Friedrichshafen AG
The longitudinal gearbox uses three multi-disc clutches, two brakes, and a new parallel-axis vane-type oil pump that enables it to be far more efficient than other automatic transmissions, with drag losses being significantly reduced due to this layout.

The dimensions have remained unchanged from the highly successful six-speed transmission it replaced, even though it has two extra gears. Moreover, weight was reduced by around 3%, making the initial 8HP70 modular system weigh just 87 kg (192 lbs.), including transmission oil.

FCA US LLC started to use this transmission on their vehicles as well, and by 2013, in order to reduce costs, they reached a supply and license agreement with ZF and started production of the transmission in the U.S. market it under the Torqueflite 8 moniker, which is used by the likes of the Dodge Challenger or Jeep Grand Cherokee SRT Trackhawk.

Jeep Grand Cherokee SRT Trackhawk
The second generation of this gearbox was released in 2014 and further maximized efficiency, with ZF claiming a 3% reduction in fuel consumption over the first generation.

Improvements included a wider gear ratio spread of 7.8:1, reduced drag torque from the shift elements, reduction in the oil pump pressure, and extended compatibility with coasting and start-stop systems.

Four years later, the third generation of the 8HP was introduced, this time fuel consumption was reduced by an additional 2.5% and the gear ratio spread was modified to 8.6. It featured several maximum torque versions, and for the first time, it was compatible with 48v hybrid power units, incorporating boosting and recuperation capabilities.

The fourth generation is set to be released soon and it will be ZF’s most versatile transmission, being compatible with traditional combustion engines and hybrid units.

ZF 8HP Transmission \- 4th Generation
Photo: ZF Friedrichshafen AG
it is equipped with an improved, highly powerful motor that further improves fuel efficiency reduces emissions even more compared to traditional transmissions and elevates the overall performance of the gearbox.

This transmission will be used in a variety of rear-wheel and all-wheel-drive vehicles, from regular, midsize to high-performance cars, SUVs, and off-road trucks due to its multiple versions that can handle engine torques that range from 300 to 1000 Newton meters.

It is a worthy alternative to dual-clutch transmissions due to its low cost, durability, and modular architecture that makes it easy to fit on a wide range of vehicles.
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About the author: Vlad Radu
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Vlad's first car was custom coach built: an exotic he made out of wood, cardboard and a borrowed steering wheel at the age of five. Combining his previous experience in writing and car dealership years, his articles focus in depth on special cars of past and present times.
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