ok now we are getting somewhere, your front axle the GMC (if its full size) is not going to work with out a new transfercase (rangers have a driverside drop, GMC has a pass. side drop). if your still thinking about my Toyota then leave the stock axles in it. the stock transmission will stand up to a 383 stroker. The axles and Transfer case will stand up to cummins 5.9 6BT and avanced adapters has an adapter for using an NV4500 with the yota t-case and a 5.9L diesel will fit with no fitment issues.
getting back to your ford. if you stay with the 4.0L then a D30 from a jeep will work fine but a D44 from a rubicon or a waggy works better and they are about the right size. of for the same amount of money you can tune your TTB and be better than a straight axle.