Avoid synthetic oils unless you want leaks. Not really needed and a lot more expensive. Many old Toyotas live long happy lives with dino oil.
The key thing is to keep the oil full, clean, and water-free, and check the vents on your axles and xfer case (pry the caps off, toss the bits, and clamp on some 3/8" fuel line and run the hose up high with a small fuel filter on the end of the line).
The key thing is to keep the oil full, clean, and water-free, and check the vents on your axles and xfer case (pry the caps off, toss the bits, and clamp on some 3/8" fuel line and run the hose up high with a small fuel filter on the end of the line).