Acura Relies on ZF for TLX Transmission

Acura takes a rare step outside parent-company Honda for a key piece of technology by using a 9-speed automatic transmission from German supplier ZF in its new TLX sedan.

Honda is a fiercely independent automaker, with a strong engineering heritage reflected in creations such as the ASIMO robot and HondaJet. Yet, TLX Chief Engineer Mat Hargett says it just made sense for the automaker to outsource a transmission for the car, given what it wanted to achieve with the vehicle.

“We set performance targets for this car, and we were going to hit these targets no matter what, and we were looking for the best solution,” Hargett tells WardsAuto in an interview.

“We felt like working with a world-class transmission company like ZF, (given) the performance of (their) product, the weight and the package was the best way to go for us,” he says.

Hargett points out the TLX’s 9-speed is not the same as the unit in the new Jeep Cherokee. Chrysler CEO Sergio Marchionne famously blamed that transmission for delays in launching the new CUV.

However, uniting the ZF transmission with Acura’s new direct-injected 290-hp 3.5L V-6 in the TLX presented its own set of problems to solve, Hargett says.

“The first time you put an engine and transmission together, with two separate control units that have never talked before, you’re going to have issues,” he says.

Adding to the complexity of uniting the ZF 9-speed with the Acura V-6 was the addition of a fuel-saving stop/start system for the ’15 TLX.

Acura developed its own starter motor to achieve the level of quietness it wanted for the system, Hargett says.

Making the ZF 9-speed automatic especially alluring to Honda was that it is 66 lbs. (30 kg) lighter than the outgoing Acura TL’s 6-speed automatic.

Hargett says the 9AT also contributes to the 150-lb. (68-kg) reduction in weight from the ’14 TL front-wheel-drive V-6 with the Advance option package to the ’15 TLX FWD V-6.

The weight loss helped Acura improve highway fuel economy 5 mpg (2.1 km/L) in the ’15 TLX from the ’14 TL.

The new Acura 4-door is estimated to achieve 34 mpg (6.9 L/100 km) highway, compared with 29 mpg (8.1 L/100 km) highway in the old TL. The 34-mpg figure puts the TLX on par with some luxury sedans using turbocharged 4-cyls., Hargett says.

Shifts are 25% quicker for the new 9AT than those of the 6AT, and the 9-speed automatic’s paddle shifters are five times faster than those in the outgoing TL with a 6-speed.

AutoPacific analyst Dave Sullivan believes the switch to a ZF transmission is more an indication “Honda just can’t do” everything it wants to in-house anymore, although the TLX with its base 2.4L direct-injected 4-cyl. is paired with a Honda-designed 8-speed DCT.

Using a ZF transmission puts Acura on par with many of its German competitors, which already source from the supplier.

Virtually all BMW models, from the 1-Series to the 7-Series, as well as the “X” utility vehicles, offer ZF transmissions, specifically the supplier’s 8HP 8-speed longitudinal automatic.

Other luxury brands using the 8HP include Audi, Jaguar and Land Rover. The versatile unit also appears in the Dodge Ram and Rolls-Royce Phantom.

Hargett is tight-lipped on whether Acura will transition to an in-house transmission in the V-6 TLX.

Hyundai paired a ZF 6-speed automatic to its 4.6L Tau V-8 in the Genesis sedan upon the car’s 2008 debut. By the time the larger, more powerful 5.0L Tau V-8 arrived in the Equus sedan in 2010, the Korean OEM had its in-house 8AT ready.

Hyundai’s 8-speed auto also has supplanted the ZF 6AT in the 4.6L V-8 Equus and the 3.8L V-6 Genesis coupe.

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