Various automatic transmissions have been featured in the F-series and Bronco, including the AOC 4-speed, C4, C5, C6 3-speeds, and the E4OD and 4R7OW 4-speeds. The difference lies in torque capacity and shift point mechanisms; the C-series uses a governor and vacuum diaphragm, the AOD uses a governor and throttle valve rod or cable, while the E4OD uses sensors and computer programming. For repairs or overhauls, professional assistance is recommended, or consider replacing the unit. Use high-temperature-resistant seals on these transmissions.