Don’t overlook to re-seal the gearbox with RTV after you have discovered the appropriate mixture. Even however they’re referred to as “gaskets”, they is not going to seal your gearbox on their very own.
If almost everything seems regular, try out adjusting the equipment-mesh. This is carried out with the mylar “gaskets” that sit among the principal gearbox circumstance and the enter/output caps. Try 
incorporating or 
getting rid of some of these spacers right up until your gears have about one/8″-one/four” of cost-free play. Pros can get replacements ($one-2) in different thicknesses, but we suggest the fast and filthy technique of chopping your personal out of a sheet of mylar.
“Groaning”, “creaking”, or “popping” all audio sort-of related over-the-cellphone. The very best point to do is to disassemble your gearbox and take a seem at the gears and bearings. The problem will typically present by itself in the way of damaged/lacking equipment teeth, toasted gears (like that photograph on our house web page), or blown bearings.
My Gearbox is Groaning/Creaking: