repacking the mig drive roll feeder GEARBOX (pix up now)

contemplating opening up this ol' MIG drive gearbox, and 'packing some grease down in there'. reason being: parts *aren't* available for this machine, EVER, so I need to give it "every best chance" for good, long service with ol' bubba here :-)

ol bubba here, actually, isn't real sure the factory ever even really DID use grease down in the gearbox, uhh, though. maybe the bearings are all sealed, and the gears themselves just had some grease 'painted on' their teeth, for all I know. OK, so who here -does- know? SPEAK UP, or forever hold your grease.

pix of the gearbox start here, just click 'next' above the pic three times:

so, uhh, what brand and type grease do YOU guys use when you're repacking your MIG feeder *gearbox*? I'd think removing the four allen-heads 'arranged in a rectangle' near the center of this image would get the gearbox cover off...

I've never, ever walked into a welding supply store and found "mig drive roll feed mechanism GEARBOX GREASE" being sold. help an inquiring mind.

yeah, I know I could remove the allens easily enough. however, having SOME idea what to expect PRIOR to (possibly) breaking, or ruining any intact gaskets 'would be a PLUS'

*thanks* guys