Here is a couple thoughts to consider, if you are going to wheel this Jeep, going with a high $$ lube like Royal Purple in the diffs maybe a waste of $$. Seems that my diff covers come off on a regular bases, water crossing, repairs, etc., so for me, the lube in my diffs doesn't last long anyway.
Also, the OEM radiators are known to rush from the inside out, so the flush maybe only a temporary fix. If you are not careful, the junk from the radiator will plug the heater core.
If you haven't already joined a good 4x4 Club in your area, you need to do so. You will meet a lot of good people, and you will learn a lot. Sometimes the best thing you can be is a wrench boy for someone. If you have an issue with your Jeep, do a search. You will probably find the solution to the problem as well as a step by step write up that walks you thru the repair process. Stu's Web site is good, but there are others. I have also found some write ups on this site that were second to none.