what is the difference between the 2 and which works better in our valks?
When I first got my Valk I was using Mobil One. About the third oil change they started adding friction stuff, so I switched to Rotella T5. It seemed to quite things down a bit. The next change Autozone was out of T5, so I went full synthetic. Slight improvement on gas mileage and a much quieter ride. I'm a believer. T6 from now on.
Thanks T.P. for piping in on this!