Don’t overlook to re-seal the gearbox with RTV following you have identified the appropriate mix. Even though they’re referred to as “gaskets”, they will not likely seal your gearbox on their possess.
If every thing seems typical, 
try out altering the gear-mesh. This is completed with the mylar “gaskets” that sit between the majo
r gearbox circumstance and the enter/output caps. Consider introducing or eliminating some of these spacers right up until your gears have roughly one/eight”-1/4″ of free of charge play. Experts can buy replacements ($1-two) in various thicknesses, but we suggest the swift and filthy approach of slicing your possess out of a sheet of mylar.
“Groaning”, “creaking”, or “popping” all audio variety-of related more than-the-telephone. The best factor to do is to disassemble your gearbox and get a search at the gears and bearings. The concern will usually present itself in the way of broken/missing equipment enamel, toasted gears (like that photo on our residence website page), or blown bearings.
My Gearbox is Groaning/Creaking: