Gimpy you were right fairly simple but due to the weight of these things not an easy task by yourself.
So here's the rundown. I got the new axle but it didn't have the axle shafts so I used the ones I had which were pitted/rusty in some spots. Water must have gotten in there somehow or possibly from condensation. Anyway, I took a wire wheel to the bad spots cleaned them and they seem fine so I put them in the new axle.
While I had everything apart I decided to buy a nice 20 gallon pressurized media blaster from Tractor Supply, that thing worked great as you can see from the pics.. I blasted off allot of the major rust down to the bare metal and then coated with Rustoleum Rust Reformer and then with a spray on bed liner.
I bolted everything back together and then it was time for fluids. Someone once gave me a bunch of waste oil and by accident gave me a 5 gallon bucket of unused 10W-30. I decided to fill up the rear differential with 10-30 to flush out any impurities since we did take off the pumpkin to inspect the teeth before I purchased it. I also checked out the front diff and the T-Case. They were both nasty, the oil was a rusty color and foamy. I did the same with the 10W-30 flush. I took it around the neighborhood relatively slow and then drained them all out and replaced with nice new 80-90 gear oil.
The truck feels great now and shifts smooth as well. An added benefit was that the rear hubs were not flipped like my original axle. This is great as the rear wheels now stick out 6" from the M105 bed and I don't have the clearance issue with the inside of the wheel wells like I had before. They don't track in the same line but I like it!
When I have the time to take the old axle apart I will post pics so you can see how chewed up it got..
Thanks again for the help guys!