I rebuilt my box and it cost me no more than about £70 for the parts. It's the labour thats a killer when you have someone else do it for you (and they aint that hard to rebuild). When mine whent i was quoted £375 to have it rebuilt. It all depends on whats wrong with yours on how much it will cost really if it's only bearings (like mine was and mine was hard to get in gear and made a whining noise in first) then you can get the full kits for about £50 it's when you need things like new shafts etc.. that the bill goes up