The Model 20 has two-piece axles, which are probably the weakest points of the whole assembly. Each axle consists of a shaft, which attaches to the differential and runs the length of the tube, and a hub, which is the flange that the wheel bolts to. The hub is pressed on the tapered end of the shaft. Often the shaft spins inside the hub, ruining the splined-portion of both pieces. Some 44s came with two-piece assemblies too, so check the axleshafts to see if they're one- or two-piece assemblies.