Hi I'm new here and also new to nissans. I got a 91 4x4 with the 2.4 4 banger. I got the haynes manual for it and was looking through for the types of oil I need. I got 30 weight for the engine and the dexron ll for the transfer case but I was looking for the tranny,manual 5 speed, and for my weather conditions here in Hawaii it dosen't get cold all year and going by that it says GL-4 either 10w-40 or 20w-50. Where do I get gear lube that thin? Or do I just use motor oil? And it says the differential is the same oil. What should I use? What do you guys use?