Download AUTOMATIC TRANSMISSIONS RE4F04A/V Electronic Controls Infiniti; I30 Nissan: Altima, Maxima, Quest *** PLEASE READ THIS FIRST *** This transaxle is also used in the Mercury Villager and is identified as a Ford 4F20E. For additional information see appropriate 4F20E article. Automatic transaxle is electronically controlled. Transaxle shifting and lock-up is controlled by Automatic Transaxle Control Unit (ATCU) for optimal performance. The ATCU receives information from various electronic sensors, switches and solenoids and uses this information to control shift and lock-up solenoid valves. For additional information and testing of these components, see COMPONENT TESTING & CIRCUIT TESTS.