Never said it was. And Torco rates its SGO superior to RGO. And of course you can't go wrong with following the manufactures recommendation. I just prefer the extra added protection that synthetic's offer.I’ve been on the phone with Dynatrac and they recommended not to use synthetic and to use Torco RGO or similar. End of story for me, that’s what I use in my PR60s. Torco is not some backwoods brand, it’s probably more expensive than most synthetic gear oil.