[rdass623]

usually when filling a gearbox, it is filled until the gear oil starts spilling out from the fill hole. if the three quarts don't get you there, you probably need more, if it does start spilling out you are full. if pelican recommends 3 quarts, it should be more than enough... just my opinion. if you need a little more, read the specs on the bottles you received and get a compatible oil from your local parts store. the A.P.I. specs should get you where you need to be.