How do I Identify a Ford Differential?by Floyd Drake III
Differentials are the gears housed within the rear end unit of a vehicle, aiding in the transfer of power to the wheels driving the vehicle. Ford vehicles use a number of different differential units, consisting of Ford manufactured differentials or those manufactured by the Dana Corporation. Identification is done both visually and by locating model numbers from the identification tags attached to the rear end housing. Primary Ford units can be identified visually, while certain Dana/Spicer units require a combination of visual and model number identification.
Count the number of bolts on the rear end housing inspection cover.The inspection cover faces the rear of the car and is seen looking forward under the the license plate. Each Ford model has a different number of bolts, however, certain Dana units have the same bolt count. According to Kevinstang.com, Ford 8 and 9-inch rear ends are removable carrier units and have no inspection cover. The back of these units have a smooth hump with no bolts.
Compare the bolt count and inspection cover gasket shape to 4 Wheel 'N' Off Road's differential identification listing. There are two headings, one for Ford-manufactured units and a separate one for Dana/Spicer units. Ford 7.5 and 8.8-inch units both have 10 bolts, however, the cover and gasket shapes are different. Similarly, the Dana 35 and 44 models have ten bolts with different cover and gasket shapes. Further identification of Dana/Spicer differentials may be necessary as some are indistinguishable in appearance, having equal bolt counts and similar cover and gasket shapes.
Find the identification tag on Dana/Spicer Corporation rear end units. According to the Dana Roadranger service manual found on www2.dana.com, Dana/Spicer differential units have two tags, one on the side of the housing and one on the differential carrier. The differential carrier tag contains the Dana model number and is located next to the driveshaft mount, facing forward on the passenger side of the housing. The model number is located on the top right hand corner of the tag, J210-S, for example.
Locate the identification tag on Ford manufactured rear end units. According to Fordification.com, the tag is located on the driver's side of the unit, mounted vertically, facing the front of the vehicle. The top line of the tag is the axle model and may consist of letters only, or a combination of both letters and numbers. It must be referenced to a Ford Axle model listing, which gives the year, original application and differential ring-gear size. Fordification.com has a complete listing of Ford axle models.
- Ford manufactured differential units are named after the diameter of the ring-gear. A Ford 9-inch differential has a 9-inch ring-gear diameter.
A native of New Haven, Conn., Floyd Drake III began writing in 1984. His work has appeared in the "New Haven Register," Medford's "Mail-Tribune" and the "Ashland Daily Tidings." Drake studied journalism at Southern Connecticut State University. After working as a reporter in Oregon, he is now based back home in New Haven.