i had to drop one of the drive shafts of my son's just purchased red rust bucket from melbourne, and the gearbox oil was black and like sludge. i guess it has never been changed in it's life, even though it changes gears perfectly and is still quiet apart from whirring when in reverse.
obviously it needs flushing and replacing, so what is the best procedure, do i drain it and fill it with something else to wash the insides(maybe like kero?) before filling with new oil?.
also, what is the oil capacity for a 5sp?

cheers
eric