What is the best oil to use in a 5 speed sunny box and also how much oil do u put in?

I use 80W-90 Synthetic gear oil, but in summer, or for a little extra safety you can run thick 80W-140 gear oil....it's super thick and takes a while to get into the tranny. Just fill it through the filler hole until it starts gushing out...usually this is just after you empty a 1 quart bottle...so if you buy 2 quarts of gear oil, you'll have enough to fill the tranny and top off the diff!

hmmm yeah what he said but it's bout 3-3.5 litres in my experience, dunno how that converts to quarts , i just run the light manual gear oil otherwise the gear change gets really chunky specially when its cold