BMW continues to purchase ZF 8-speed automatic transmissions, further developed

BMW and supplier ZF have agreed today in a long-term supply contract on the further development of the 8-speed converter automatic transmission, abbreviated as "8HP", which has already proven itself in several vehicle generations. The transmission developed by ZF is to be further developed until the late 2030s "with a special focus on electrified drives". According to a press release jointly issued by both companies today, the contract comprises a volume "of several billion euros".

Focus on Hybrid

"Focus on electrified drives" means that the existing unit is to be expanded for use in future hybrid drives. Through the basic design of this transmission, BMW is committed in two respects: firstly, to the longitudinal installation of the combustion engine, and secondly, to an electric motor concentric to the transmission shaft. The electric motor can be located with the torque converter clutch or an automated starting element in the bell housing or in the transmission housing. A combination of both installation positions is also possible.

ZF is in a severe crisis due to the weakness of the German automotive industry and recently planned to end up to 14,000 jobs in Germany by the end of 2028. Numerous employees in Germany are already on short-time work. With around 161,600 employees in 161 plants in 30 countries, ZF is one of the largest suppliers in the automotive industry and generated sales of around 41.4 billion euros in 2024. In 2023, it was still 46.6 billion, and a further deterioration is to be expected for the 2025 results. ZF will present the figures for 2025 in March.

Conventional, modular design

With four gear sets, the current 8HP version uses only five shifting elements. Because only two shifting elements are open per gear, drag losses in the transmission are significantly minimized. ZF was also able to reduce the number of multi-plate clutches to three and brakes to just two. The consistent friction minimization, to which an axially parallel vane cell pump also contributes, enables internal combustion engines used with the 8HP to achieve higher efficiency.

Available in various versions for engines with a torque of 220 to 1000 Nm, it is also used by other car manufacturers, for example Audi.

The modularity of the 8HP system allows for a plug-in hybrid transmission with an integrated electric motor of up to 160 kW and a maximum torque of 450 Nm, using largely conventional components. The conventional design "reduces the need for installation adjustments and the associated investments for the customer to a minimum", as ZF itself writes.

(fpi)