Stellantis is developing a multi-speed transmission system for electric vehicles (EVs) as part of efforts to improve efficiency, according to a recently disclosed patent filing.
The patent, published by the United States Patent and Trademark Office (USPTO) on Feb. 27, 2025, but originally filed in 2023, details the integration of a second forward gear into drive modules commonly used in EV powertrains. The filing primarily discusses how the system would manage gear shifts and proposes the use of magnetic fluid for actuationāa technique employed in adaptive dampers.
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“This fluid contains ferrous metallic particles, which react to magnetic fields,” Stellantis stated in the patent. The automaker claims this approach could allow for more efficient gear engagement compared to traditional hydraulically actuated clutches.
The filing refers to “electrified vehicles” rather than just battery-electric models, suggesting potential applications in hybrids and plug-in hybrids, including Stellantisā Chrysler Pacifica Hybrid and Jeep 4xe models. Multi-speed gearboxes in hybrid systems are not new; Mercedes-Benz employs a two-speed transmission in some of its AMG plug-in hybrid models.
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This marks Stellantisā second recent patent related to multi-speed EV transmissions. A previous filing, published in January 2024, focused on off-road applications with a different gear-actuation mechanism.
Currently, the Porsche Taycan remains the most notable production EV utilizing a multi-speed transmission. Other automakers, including Mercedes-Benz and Lucid, have explored similar systems, while Volkswagen has ruled them out. Honda, meanwhile, has taken a different approach by designing a manual transmission for its upcoming 0 Series EVs.