I recently sold a couple of ATV's. Now that they are gone, I've got four bottles of Amsoil Synthetic 4cycle 0w-40 left. My question is this; can I use them for my Ranger (5w-20 or 5w-30 recomended) if I was to reduce the overall viscosity by mixing a couple of bottles of Amsoil 5w-20 per two bottles of the ATV oil? The ATV oil doesn't have any friction modifiers, so does that really matter? Are there other things absent in this oil that I should know about? It does say on the bottle that it CAN be used in a car, but that it's not ideal. Any concerns that any of you folks would have doing what I propose? As a precautionary note, I will be keeping it to a 5k oci....just to be safe.