hi im sorry i do normally try to help if i can but i do have alot to think about,and do need reminding,without going further theres not much (oil pressue test and the stripping )i can say without more info,as long as selector cable is secure to box,it would seem free wheel clutch or more than 1 or valve block,if you where over here i wouldnt mind stripping it and sourcing fault ,but it will need removing and replacing,as valve block would be more expensive than another box,which can be done yourself if access to engine crane etc to lift box through tunnel in car,i dont mind answering any questions but do need pestering ,sorry martin