The original axle is well up to the task, the only real problem is a lack of support in the aftermarket for items such as gears and locking mechanisms. The trans will work just fine, but unless you get an adapter, you'll have to use a divorced style transfer case. Another hangup you'll have is the chassis itself. The 4x4 '60-'62 trucks used a different chassis that the 2wd trucks. The 4x4 is more like the '55-'59 is basic layout, and doesn't have the extra X member that the 2wd trucks do. I won't say it can't be done, but there will be alot of fabrication involved. Do your planning, and make sure any parts you decide to use will work. I would suggest perhaps looking for a later model doner truck, get the complete chassis and driveline. That will give you a matched driveline (look for a 3/4 or 1 ton w/full floating axles) and the option of adapting the suspension to your existing frame or cutting down the late model frame to fit your trucks body.
