Can someone reccomend what oil to use in the rear diff and gearbox of a 2001 4 Motion ? I have been looking at VW oil, but is expensive for what it is. Does anyone know what other makes of oils will suffice ? Am i right think fully synthetic is best ? Does anyone know if i need a 80w,85w or 90w oil ? And how many litres i need ? Help and Suggestions are appreciated. Richard