What kind of gear oil should I run in my diffs? 4:11 gears, no lockers, no posi, just standard gears. FJ62 with auto trans and 33" tires. I was looking at some synthetics, should I run 90w or something else?
80w-90 hypoid gear oil will work. Synthetics will provide better lubrication but will also leak out of questionable seals. If you've never done the seals stick with regular oil, if you've done the seals recently go with synthetic.