Our 2024 Mazda CX-90 PHEV’s Transmission Leaves Much To Be Desired

It is time to talk about the 2024 Mazda CX-90 PHEV’s transmission. We first noted our issues with it soon after our yearlong review example was delivered to our Los Angeles office, where buyer’s guide editor Zach Gale gushed over the interior but noted, “Gosh, does Mazda have refinement work to do on this powertrain.” He expressed fears for first model-year owners “who have to deal with the needs-improvement transmission behavior and strange noises at low speeds.” 

Then colleague Miguel Cortina penned a first test of another CX-90 PHEV, and this one also experienced issues. “At parking lot speeds,” Cortina said, “the eight-speed transmission felt jerky when coming to a full stop, and although it wasn't frequent, it's something that needs to be addressed in future updates.” We noticed issues during SUV of the Year testing too, like slight lurches during shifting, especially in electric mode at low speeds, though we praised the transmission’s calibration at higher speeds.   

Shudder, Hesitate and Stutter 

The change in scenery for our long-term CX-90 hasn’t helped much. Since driving it out to our Detroit office, numerous editors have spent time behind the wheel, and the reaction has been universal: The transmission tends to shudder and hesitate. The stutter usually occurs after a full stop and at slow speeds. It doesn’t happen all the time, but when it does, it can be jarring enough to make daily driving unpleasant. 

Testing director Eric Tingwall did a nice job of explaining what he encountered: “The transmission is generally well-behaved when the gas engine is running. In EV mode, it occasionally makes a hard and abrupt shift, which always reminds me that even when operating purely on electricity, most PHEVs can't match the smoothness of a full EV. That's really noticeable during the transition from EV to hybrid operation, when the powertrain regularly stumbles. First it seems to cut electric power, then it suddenly feeds in the gas engine with too much torque.”

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Mazda Explanation

We reached out to Mazda for more information about the novel eight-speed automatic transmission in the CX-90. It was developed in-house by Mazda, which has a history as an engineering company. The official explanation: “This design eschews the conventional torque converter for a multiplate wet-clutch setup, which not only improves efficiency by offering more direct transfer of power from the engine to the drive wheels but allows for a more connected driving experience. In certain circumstances, this can result in increased powertrain feedback.” That “feedback” should not be excessive or otherwise particularly notable, we were told.  

One of the most common complaints about a multiplate wet-clutch transmission like those commonly found in dual-clutch automatics is that the transmission tends to jerk and lurch when driven at lower speeds, such as in a parking lot or when the car is in reverse. However, we’ve collectively put thousands of miles on other vehicles with wet-clutch transmissions instead of a torque converters, and the experiences are largely smooth and flawless.  

That has not been our experience with the Mazda version.  

Other Mazda Owners Agree

And we are not alone. Other owners have taken to a CX-90 forum, complaining that the plug-in hybrid has a tendency to shudder and hesitate when accelerating from a stop or at slow speeds. One described the jerkiness as akin to someone trying to learn to drive a manual transmission, especially the shift from first gear to second if you accelerate lightly. Other owners have suggested it becomes less noticeable over time as the vehicle learns driving habits, or people have just gotten used to the slight jerkiness and subconsciously adjusted how they accelerate. Our multiple drivers have not noticed a similar improvement, and Mazda says that although a vehicle might operate more smoothly over time, there is no learning of driver behavior.

More Widespread Than We Thought

We wondered if the problem is unique to the CX-90 PHEV, but all variants of the CX-90 share the same transmission, Mazda confirms. There seem to be fewer complaints, anecdotally, with the low-speed shifts in the regular models powered by the company’s new inline-six. MotorTrend’s experience with our long-term 2023 Mazda CX-50—which was not a plug-in hybrid and which has a six-speed transmission—also gave us pause. “At low speeds, it delivered a hiccup or slight jolt, as though it needed to catch up to our intentions,” Gale wrote in his verdict. “The trait didn't happen every day and never happened at a dealer.” We had similar complaints about our CX-30 before that. 

We appreciate Mazda’s efforts to engineer its own transmission—and certainly this is an industry where not many get everything right on the first try—but to maintain its reputation and appease its customers, Mazda needs to refine the drive experience so that acceleration is smooth at all times and at all speeds, for the satisfaction of all customers. Here’s hoping a software update can smooth out our CX-90’s transmission. 

More on Our 2024 Mazda CX-90 Long-Termer: 

• 2024 Mazda CX-90 PHEV Yearlong Review Arrival: Feeding My Mazda Habit

• A Cold Cross-Country Trek in Our 2024 Mazda CX-90 PHEV Gets Into Tire Trouble 

• How Do Cold and Snow Affect Our 2024 Mazda CX-90 Plug-In Hybrid?