I have my undertrays off ready to check gearbox oil level I have located the drain allan bolt at bottom of gearbox but for life of me cannot locate a filler hole on the side or anywhere to measure the level as I have a allan bolt on top of gearbox to add oil and do not imagine filling all the way up to that level, can anyone shed some light on this please as I have a elearn manual with no diagram and seems very different to petrol stilo gearbox it is an 04 multiwagon 115jtd