With synthetics, make sure it DOESN'T have the EC code; if it does, it probably will contain friction modifiers & cause clutch slippage. Mobil 1 15W50 does not have the EC code (the other weights do). I notice that in tight technical sections, I'll find neutral alot more often with gearbox oil that has over 200 miles. This has been somewhat repeatable with Mobil 1, Spectro, or Bel Ray. I'm not sure why, but fresh fluid really does make a difference. Remember that the next time you hunt for 1st or 2nd on the middle of a steep, single track, muddy, rock strewn hill; I hate when I miss that gear and crash infront of my buddies :yeehaw: