Hi first off I will apologise if I am at the wrong section and I thank anyone in advance for any replies. Just serviced the haldex on my 4mo and all good.I want to change the gearbox oil and just wanted a little advise please. Have been told you need this mad socket to drain the oil is this true? Also I have been told the gearbox takes 2.8 litres which also feeds the transfer box. Is this correct or do you need to fill the tbox separately. 1 more thing.lol. TPS tell me gearbox and rear diff oil are same oil but vw say rear diff oil is different. Any advice would be greatly appreciated.