I'm not sure that chain lube is the right stuff for a gearbox. We've used some stuff by Mobil in the past like
http://www.amazon.com/Multipurpose-Grease-XHP-222-14-1/dp/B009VGEEM4/ref=sr_1_2?s=automotive&ie=UTF8&qid=1397415677&sr= 1-2&keywords=mobil+grease
but this stuff seems to just go everywhere, so we're now using red and tacky, which is made for these sorts of open gearboxes. It is the best.
http://www.amazon.com/Lucas-Oil-1000.../dp/B000ARPVO8