Gearbox Lube

When replacing pump and belt about 1/4 cup of very sticky gear lube leaked from the gearbox while the machine was laying on its side. Should I replace the amount that leaked out? Is there an easy way to add new gear lube? Is there a spec for the type of lube that should be used?

It is important to add oil as low oil will burn out the upper bushing. I would use 90 weight gear oil. Pull the tranny and with a sharp wood chisel, punch a slit in the top cover, enlarge it and add oil. When done, clean the area and seal with silicone cement (RTV) sold at Wall Mart.

Thanks for the advice! That seems perfectly feasible.