3.5 litres for main gearbox,can't remember for transfer box.-but what does it matter? On both boxes drain oil from bottom plug,replace and fill to level of filler holes on side of both boxes. Make sure you are on level ground so that you don' overfill.If oil from transfer box is a different colour it's auto transmission fluid-replace with same-do not mix! It is difficult to access the filler hole for main box,so get some plastic tube that will fit over the nozzle of the oil bottle-about 3 ft. Will do.Hope this helps!