If there is any movement in your UNI's then, grease em up/replace them. Also look for movement in your slip joints in your tail shaft.
Drain your Gbox, Transfer and diffs, then refill with VMX-80, or the EPX90 I left behind my car

While draining your oil's you can see if there is any chuck of steel, or fillings. You can, with a good torch and eye see the teeth on the diff see if any look damaged, but your probs going to see diff parts come out with oil before you see missing teeth haha.
Also, I think there is a 5speed Vit box and transfer case behind my tool chest. There yours if you want them.