You are going to get a lot of different opinions on the gear lube issue, GL1 vs GL5. The story goes that GL5, your typical modern gear lube thats available everywhere, has EP (extreme pressure) additives in it that will attack synchros in your t/case and trans. Remember, the deuce t/case is synchronized. Some will say they have run GL5 in a synchro'd trans for years with no problems. The axles should not have a problem with it, though.
GL1 may be harder to find in the appropriate weight. I worked on my local auto supply house for 2-3 months before they got some. None of the Tractor Supply Co or similar places had it.
Regarding engine coolant, use low silicate coolant made for diesels, and ck your Ph levels, adding the diesel coolant supplement if necessary. Not doing this CAN lead to cavitation (pitting) in the cylinder liner walls.
For engine oil, be sure you use a diesel rated oil (CH-4 or CI-4). Rotella 15w-40 is the most common stuff available just about anywhere. They even sell it at Sam's club here for roughly $35 for 6 gallons, enough for one oil change.
