Ford F250 trucks are known for their endurance and versatility. That extends to the transmissions Ford used in the 1990 trucks. There were four transmissions available, and the customer was able to choose the right one based on personal preference and intended use. All four are capable of heavy use and towing capacity.
The AOD high-performance automatic transmission for the 1990 Ford F250 is equipped with overdrive. This transmission can be identified by the P-R-N-OD-D-1 configuration on the gear shift. With the standard meanings for each symbol being P for parking, R for reverse, N for neutral, OD for overdrive, D for drive and 1 for first gear. This transmission can be shifted into overdrive instead of having an overdrive cancel switch.
The E4OD is also a high-performance automatic transmission. The main difference being that this transmission does not have an extra gear on the shifter for overdrive but instead comes with an overdrive cancel switch. Turning your overdrive off means that your 1990 F250 will not shift into fourth gear. This can be useful on uphill climbs but will be murder on your gas mileage for standard driving needs. The E4OD transmission can be identified by the P-R-N-OD-2-1 configuration on the gear shift. In this case, OD also represents the "drive" gear with the transmission automatically shifting into overdrive when needed.
Used in Ford's 1990 F250 gas and diesel engines, the C6 3-speed automatic transmission was designed to endure heavy use. Towing and hauling heavy loads are the top intended uses for the C6. Today the C6 is sought after for drag racing because of its ability to generate power. It is also one the least-efficient transmissions because of the power needed to operate it.
The stoutest transmission available in the 1990 F250 was the ZF. A 5-speed manual transmission that was used in gas and diesel engines. This manual transmission was intended to accommodate the heaviest hauling and towing the F250 could provide. The ZF gave driver's more control over their gears and shifting needs, which in turn provided for better gas mileage.
