Still want to swap some parts? Then get familiar with this illo, find the numbers on your axle, and make good friends with your Dana parts distributor. The build-date code (1) tells you if the disc brake 44 on your '72 is original. It reads from left to right: month, day, last digit of year (e.g., a '72 has a 2 stamped in it), shift that built it, and production line. But the critical number is the bill of material or part number (2). These seven digits allow someone with the big Dana-Spicer spec books to find axleshaft dimensions, spline size and count, U-joint specs, and more.