F4A51 Transmission Valve Body for Hyundai and Kia

Replacement valve body for the Mitsubishi-designed F4A four-speed automatic used across Hyundai and Kia, covering the F4A41, F4A42 and F4A51 variants. It supersedes OE numbers 46313-39051 and MD758981, so it is the unit you order when the original casting is worn, cross-leaking, or has a stuck valve you cannot clean up.

The F4A family gets its problems from bore wear and varnish, not from the electronics. Typical symptoms are a delayed engagement into drive after a cold start, a harsh or slipping 1-2 shift, a flare between 2-3, loss of third or fourth, or the transmission dropping into limp with shift solenoid and TCC codes stored. Once a bore has worn oval, line pressure bleeds off past the valve and no amount of fluid or filter work brings the shift back. Swapping the valve body is the repair that actually restores pressure.

Bench work is straightforward with the pan down. Drain the fluid, drop the pan and filter, unplug the internal solenoid harness connector, then work the valve body bolts out in a cross pattern and lower the assembly straight down so the manual valve pin stays on the detent lever. Compare the new unit against the old one before it goes in, confirm the check balls and separator plate layout match, and transfer any solenoids the new body does not include. Torque the bolts evenly, fit a new filter and pan gasket, then refill and relearn the shift adapts.

Confirm your transmission tag before ordering. The F4A41 sits behind the smaller four-cylinders, the F4A42 behind the 2.0 to 2.4 liter four, and the F4A51 behind the V6, and the valve bodies are not interchangeable across every year and calibration.