Never neglect to re-seal the gearbox with RTV soon after you have discovered the proper blend. Even however they are referred to as “gaskets”, they won’t seal your gearbox on their very own.
If every thing appears standard, consider changing the gear-mesh. This is carried out with the mylar “gaskets” that sit in between the primary gearbox situation and the input/output caps. Try including or eliminating some of these spacers until your gears have roughly 1/8″-1/4″ of free of charge play. 
Pros can buy replacements ($1-2) in various thicknesses, but we suggest the quick and soiled approach of reducing your personal out of a sheet of mylar.
“Groaning”, “creaking”, or “popping” all seem sort-of equivalent in excess of-the-mobile phone. The best point to do is to disassemble your gearbox and take a look at the gears and bearings. The issue will generally current alone in the way of broken/missing gear tooth, toasted gears (like that photograph on our home web page), or blown bearings.
My Gearbox is Groaning/Creaking:
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