www.mobile.com go to other products and itgives very specific data on their products!! their gear lubes are synthetic according to their website and beleive me if ya call them they are more than glad to shoot ya a straight answer! just do not ask them about other manufacturers products cause ya will not like their answers!! thei products work for the turn left and matt it nascar boys and if it work for them it works for me!! just stick with the toyota 5K mile intervals!! and watch closely which ratings are applicable to which engines/year models!! i have a 2006 dcab tundra and just switched to 5w30 truck and suv cause it has more addatives to keep engine cleaner than straight 5w 30!! call them with any question and the are very responsive!!