In the mid 1950s, what most folks now call the Dana 44 Standard Closed Knuckle Axle was referred to as a Spicer 44 Front Drive Axle. International introduced the 7000 pound Gross Vehicle Weight (GVW) R-120 3/4 ton 4x4, the firm's first factory 4x4 pickup late in the 1955 model year. The R-120, which featured a FA-15 standard Spicer 44 closed knuckle front drive axle was quickly superseded by the mechanically similar 1956 S-120 4x4. In addition to updated front end sheet metal, S-120 4x4s were offered in pickup, stake, and utility body versions, plus enclosed body panel and Travelall models. The 3/4 ton FA15 was the sole production 4x4 axle choice International offered for pickups up to and including the 1960 B-120. International pickup truck buyers had 2 axle choices for the 1961 C-120 which could be ordered with either a FA15 standard Spicer 44 or a FA18 Heavy-Duty Dana 44 front axles which have a higher weight rating, larger axle u-joints, and larger knuckle bearings. For 1963, International brought out it's first factory 1/2 ton, the C-1100 which came with a FA16 Spicer 44 Closed Knuckle front axle using internally splined wheel hubs. The FA16 1/2 ton and FA15 3/4 ton axles were used in production IHC vehicles until the 1971 model year although Dana does list the FA16 for 1972. FA18 and the similar FA25 3/4 ton axles were used in production IHC vehicles through the 1973 model year although Dana does list the FA18/FA25 for 1974 and 1975.
