I grease every loco I get,usually .5-1.0 ml is enough in the gearbox screw, the other screws are primarily for axle bushings and just a small squirt will do. Once theres adequate grease theres really no reason to add more IMO it cant really go anywhere. Legacy diesels are my biggest offenders when it comes to "lack of factory grease" removing a couple sets of phlilps heads on the bottom of the trucks allows access to the worm gear. At the suggestion of other members I use lucas red n' tacky a big tube of it can be found at the local auto parts store for $4.00. This grease stays where its put and doesn't break down and seperate like the white lithium greases do. I use a leftover baby medicine syringe for greasing.On a side note I use labelle 102 on the rods and linkage, its a "heavier" light oil and stays on the pivots better reducing the need to reoil.