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Jeep, Chrysler, Acura 9-Speed Automatics: Supplier ZF Offers Tips

2015 Jeep Cherokee

2015 Jeep Cherokee

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The arrival of nine-speed automatic transmissions—with some hiccups in tuning—in several mass-market models this past year has led some to wonder whether more speeds is necessarily a step forward.

While the better mileage and stronger acceleration that more speeds can allow, drivability, it seems, has been lacking in some—yet not all—applications of the ‘9HP’ nine-speed automatic, from the German supplier ZF, that was introduced in 2013 and then more widely installed beginning this past year. Complaints about the Cherokee—either before or after an early reflash of the transmission control software—have ranged from harsh shifts to odd shift points for this transmission as it’s installed in the Jeep Cherokee, which was one of the first models to launch with it.

The ZF nine-speed is currently installed in the Cherokee, as well as the Jeep Renegade, Chrysler 200, Ram ProMaster City, Land Rover Range Rover Evoque, Land Rover Discovery, Acura TLX, and Acura MDX—and it’s on the way for several more vehicles within the next model year.

This past week, as part of a ZF tech day, we got a chance to drive several different vehicles back-to-back, and confirmed our earlier driving impressions: that it isn’t entirely the fault of the transmission. The same unit’s somewhat softer, more conservative calibration works to the benefit of drivability and smoothness in the Discovery Sport, versus those Jeep models, for instance.

Not properly fleshed out to American driving styles?

ZF officials are acutely aware of the drivability concerns. “First of all, we learned that Americans drive differently,” said CEO Stefan Sommer, as part of a Q&A session. “We need to focus more on the regional-specific perception of how such a complex machine like an automatic transmission is working in the car, and as a consequence we have made a decision to bring more application engineering into the U.S….to be closer to the U.S. customer, to even frontload, in this tuning application work.”

Sommer called the new design of the 9HP “an encouraging new approach” that makes nine-speed technology available in a vehicle segment where it otherwise wouldn’t have been available; yet he noted the unusual arrangement, where ZF did the engineering and automakers oversaw the build (and shift strategy).

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