Just going a bit further here. You said
And also, when a Vari-Lock diff. wears out, does it function similarly to an open diff, where as it can still be used and "locked" via my tcase, but will not engage tire slippage from wheel-to-wheel across the axle?
back at post 15. The diff will never work or act like a locking differential, meaning that if it is worn out 2x4 or 4x4 will not make it "lock", it will be just like a open diff. Now when it's operational, it will work when engaged in 2x4 or 4x4 when slippage occurs enough to cause pressure to build and squeeze the clutch packs. But it will still slip, and can slip, if it's worn in 2x4 or 4x4 because of various issues (age, wrong fluid, maint history, clutches worn, etc).
So brings me back to why a QD? A regular dana 30, and a used lunchbox locker from a TJ would be more serviceable in the future and may even be cheaper than that high mileage qd axle. When I say serviceable, I did not see a rebuild kit for the front differential clutch/pump assembly. Also, since the shafts are different sizes, you can not simply put a tj locker in or even a arb or Eaton.
Now if your fixed on a qd axle, and if you are still in the westminster area, I used car-part.com to locate a 45k qd axle for $450 bucks and is located in denver (like 10 miles away). If you wanted a regular axle, the have them too, but are way to high in my opinion. Also, check out CL for someone parting one out.
And lastly, take all advice here with a grain of salt and do your research. gold01wj is simply wrong that 50 ft-lbs will be enough to set your pinion nut back on. Check out this excerpt
11. Using a tool to hold the yoke, torque pinion nut to 255 ft-lbs. Do not simply hammer the nut on with an impact wrench, as the torque on the nut has a direct effect on pinion-bearing preload. Then
Figure 26 – Measuring pinion-bearing preload
12. Measure pinion-bearing preload by using an inch-pound torque wrench. You must measure the torque it takes to rotate the pinion by the nut while it is in motion. If you simply measure the torque it takes to start the pinion rotating you will get an artificially high reading. This is why a dial-indicating torque wrench is best as you can start the pinion rotating, then read the indication from the dial while you continue to rotate the pinion. Preload should be 20-40 in-lbs for new bearings, and 10-20 in-lbs for used (i.e. set-up) bearings.
Courtesy from a more hardcore forum and user who has changed several. http://www.pirate4x4.com/tech/billavista/Gear_Setup/
The hard part for me is I don't want to buy a inch/lb torque wrench and I can't find one to borrow. I try and nab on on ebay from time to time, but they go in the 60-100 buck range. The click style are 10 bucks all day, but you need one of the dial style.
I think you'll get lucky and be easily able to find a axle with the yoke on it you already want. Try and find one with everything on it, including calipers. You can part your old axle out by selling the calipers and knuckles on here. This way you don't have to mess with it.