First of all you should do your own oil changes (save the reciepts) and I would switch over to synthetics, I use Mobil 1 15w-50? (red cap), I can't find some of the other oils people on this site recommend up here in AK. I change my oil every 3,000 miles, which I guess is a little much when using synthetics, but it won't do anything but good.

I would switch all your other fluids to synthetics also (transmission/transfer case/differentials) people reccomend stuff called Royal Purple, but I can't find that here either. Do a search on "fluids","Royal Purple", and "Mobil 1" and I'm sure you will find what you want.