This is a page out of the 1961 supplement manual. The 1960 shop manual doesn't have any info on 4x4, and I believe the 62 supplement has even more info.
picture If your truck has the original running gear, it should have a Rockwell (Timiken) T-221 t-case, and a Dana 44 front axle with enclosed u-joints. The rear probably looks similar to mine, with a drop out center section like a F*** 9". I don't know that the Dana 60 had been invented yet, but I could be wrong. Check out my webshots pics and see if yours is the same. Do you have any pics of your truck? Hope this helps...