Did the exchange yesterday. Put Mobil fully synthetic GL-4 75W80 in the transmission, GL-5 75W90 in the transfer case and front axle. Quaker State fully synthetic 75W90 Limited Slip in the rear axle. Funny thing, when I was crawling under there I found a sticker under the dirt on the housing saying "Only LSD oil". I wasn't 100% sure the truck came with LSD from the factory but now I know. Gotta say the transmission feels smoother now <img src="/forums/images/graemlins/cheers.gif" alt="" /> There wasn't much metallic residue on the magnetic plugs. Hopefully the drivetrain will hold a few more years now! Too bad the rest of the truck has seen its best days <img src="/forums/images/graemlins/rolleyes.gif" alt="" />