Mazda F21 (AWTF-81SC)

Mazda's transverse six-speed automatic — in the CX-7 and CX-9.

It is an Aisin TF-81SC under a Mazda designation, which is the connection worth making: the same gearbox is in the Ford Mondeo, the Volvo S80 and the Land Rover Freelander 2, and its service literature is far larger under those names than under this one.

Its recurring failure is the valve body and the torque converter. The symptom sequence is a shudder at light throttle — the lock-up clutch — then a harsh or delayed engagement, then a flare on one change. The first stage is a fluid-condition symptom and by far the cheapest place to intervene.

The CX-7 and CX-9 are heavy vehicles for this transmission, and heat is what shortens its life: towing and stop-start traffic age the fluid far faster than the odometer suggests.

Mazda's ATF-FZ is specific and not a generic ATF. A unit filled with a universal fluid shudders whatever else is done to it — the same trap as on the SKYACTIV-Drive.