API GL-1 Straight mineral oil
API GL-2 Mild EP for worm gears
API GL-3 Mild EP for spur and spiral bevel gears in axles and transmissions
API GL-4 Medium EP, MIL-L-2105 quality, moderate severity hypoid gears, manual transmissions
API GL-5 High EP, MIL-L-2105D quality, all hypoid axles, some manual transmissions
API GL-6 Extra high EP, now obsolete

i think the info you are giving are oil grade for gear boxes. RVISMANOS is asking for engine oil not gear oil!!!

API SA-SG are obsolete oils and API SJ, SL, SM are the new 1s for gasoline and API CA-CC are obsolete API CD-CH are the new 1s for deisel. since our country doesent have winter season and the lowest ambient temperature (in baguio) is 10 degreee celcius. single grade oil like SAE40 is can also be use. SAE rating is for the viscosity of oil. since oil becomes thick when cold and thin when hot.multi grade oil like 20W50 prevent the oil from getting to thick when temp goes below ZERO deg and to thin when temp goes high up to 40 deg.

so choosing the kind of oil you think best for you is for you to deside and think of the API rating not just the SAE.