Ford AX4N / AX4S

Ford's transverse four-speed — in the Taurus, Sable, Windstar and Lincoln Continental.

It descends from the AXOD, and the names run AXOD → AXOD-E → AX4S, with the AX4N a parallel design for the higher-output engines. Four names, two gearboxes, and parts listings that treat them as one — the engine and the model year decide which is fitted.

Its best-known failure is the forward clutch and, on the Windstar particularly, the whole transmission's reputation for not reaching high mileage. The symptom is a slip from rest or a flare on the 2–3 change, arriving warm at first.

But the fault most worth eliminating first is much cheaper: these run their torque converter lock-up hard, and a shudder at light throttle is the converter rather than the clutches. On a transmission with this reputation the temptation is to assume the worst, and the fluid's condition is the fastest way to find out whether that is warranted.

The pump and the reaction shaft support wear on high-mileage examples, producing a delayed engagement that is present when cold and clears as the transmission warms — which is the opposite of a clutch fault and worth distinguishing, because it points at pressure rather than at friction.