The input shafts are different, the auto is 23 spline, and the manual 29. Which uses a bigger input bearing & seal also. When i converted my 2wd auto, to 4wd nv4500, i had the t-case machined out for the bigger bearing and swapped the shafts since the donor truck was auto. You can find out alot of info at quad4x4.com
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93 W250 CC LE, NV4500 & SBC, pod's, pdr hx-35/16, pump & timing mods, 3200gs, pro comp auto meter gauges, 5" miter cut stacks