What's the Diff?

Making a Wood Bros. Differential Gear Out of a Free Pattern

The pinion placed on the differential and the casting machined with the spider gears, or beveled gears, back inside the windows on the spider of the differential. Notice the difference between the oil tube and the completed casting. Mike Murphy added 1/8-inch pipe, bent it to fit the contour of the casting and put a grease fitting in the end of the pipe.