i use a grease gun to do everything on the car. not sure if its just my gun, but the end is a perfect snug fit in the fill plug holes of the diff and gearbox, and you get a lot more oil in per 'pump' than with the little cans, which i also have tried, until my arm nearly disintergrated as it took so long. however, it is hard to tell how much is going in when doing the trunnions via the nipples, so next tiem i might remove them as you have done.