The reason the tranny is mounted upside down is that the engine has been forward mounted, not rear as usual for these engine so if the diff was mounted around the right way up you would have four reverse gears and one forward, so fitting the gearbox upside down swings the diff to the opposite side of the pinion and awwla you solve the problem and you have four forward gears with the engine forward mounted successfully simple solution to a complexing problem VW's, ahh so versatile.![]()