M5R4 Archives - Transmission Digest
Ford’s New M5R4: A Radical Design Change in Rear-Wheel-Drive Manual-Transmission Technology

In 2002 Ford introduced a new four-door model of the venerable Explorer and its sister, the Mercury Mountaineer. The manual-transmission option for the new four-door model is a five-speed fully synchronized unit designated the M5R4 or M5OD-R4. The M5R1 transmission we all know and love has been replaced by a radical new design built by Mazda. This unit bears no resemblance to the M5R1.