87 B II. Going to change the fluid in both axles. What is the proper weight of fluid. It has at least 100,000 miles on the old fluid, axels have 200,000 miles on them.

 

Standard answer is 80/90 gear lube. If you have a trac-lock rear, you're supposed to put friction modifier in it, but at that age, unless you 've replaced the clutches, it probably doesn't work anyway. Might be a good time to replace them, while you have it open.