* Check the axle tag: Look for a tag on the differential housing itself. This tag usually lists the gear ratio (e.g., 3.50, 3.73, 4.10).
* Inspect the ring and pinion gears: This requires removing the differential cover (and potentially some other components). Counting the teeth on the ring gear and the pinion gear allows calculation of the ratio. This is a more involved process requiring mechanical skills.
* Consult a Ford parts catalog: Using the vehicle's VIN number, a parts catalog (either online or via a Ford dealership) might list the axle ratio for your specific truck. This is a good method if you have the VIN.
Without either the axle tag information or access to a VIN-specific parts lookup, determining the exact gear ratio is impossible.
