I'm Not Jed Clampett
Is the axle whining on drive, overun or all the time? If you're using an old car rear axle in your truck, you might have to change it out a few times for other secondhand ones till you luck into a good one. 60s/70s yanks will probably have done Starship Enterprise mileage by the time they reach the breakers yard. A new CW & P and bearings for your existing axle would probably work out cheaper -and easier than repeatedly changing out the rear axle.