Don't use gear oils in engines. Some/most gear oils have sulphur compounds which attack the coatings on the rod, main and cam bearings. Don't use regular grease either as the base component will get stuck in the oil filter reducing its service life significantly.
Vasoline/petroleum jelly is the best choice as it dissolves in oil, has no harsh additives, and has no base to gum things up. You can also use Lubriplate 105 engine assembly grease as it behaves similarly.