Best grease for gears?

[sanddrag]

Regarding gearbox breakin:

I once had a gearbox that sounded awful, and was clearly binding. I put it on a power supply, and the meter showed the one CIM was drawing about 8 amps with no load on the gearbox. So, I took some car polishing compound I had on hand, squirted some in the gears, ran it for a few minutes adding a little more compound periodically, and watched the current draw drop to about 2.5 amps. Now that's more like it. Cleaned it out, greased it up, and it was good go. A mildly abrasive compound seemed to really break it in quite nicely. I'd be careful to keep it out of bearings though.