You don’t see these everyday. The Timken rear axle was a heavy-duty spiral-bevel axle of the day. These split-case axles were a legacy of the ’30s and ’40s, but faded away by the mid-’50s. This axle was replaced by a Dana 53 starting in 1954. It was a decent piece in the day, but a bit tricky to set up. Today, internal parts like ring-and-pinions are nearly impossible to find new (NOS). The 4x4s in the 1948 era had no gearing options besides the 5.38:1, but the 4x2s were offered with 4.88:1 and 6.17:1.