Never forget to re-seal the gearbox with RTV right after you’ve located the proper blend. Even however they are referred to as “gaskets”, they is not 
going to seal your gearbox on their own.
If everything seems regular, attempt altering the equipment-mesh. This is done with the mylar “gaskets” that sit among the primary gearbox scenario and the enter/output caps. Consider including or getting rid of some of these spacers until your gears have approximately one/eight”-one/4″ of totally free perform. Experts can purchase replacements ($one-two) in varying thicknesses, but we advise the swift and filthy method of reducing your personal out of a sheet of mylar.
“Groaning”, “creaking”, or “popping” all seem type-of comparable 
over-the-phone. The greatest issue to do is to disassemble your gearbox and take a search at the gears and bearings. The issue will typically present by itself in the way of damaged/missing gear teeth, toasted gears (like that picture on our residence page), or blown bearings.
My Gearbox is Groaning/Creaking: