Do not overlook to re-seal the gearbox with RTV right after you have located the correct mixture. Even even though they are named “gaskets”, they won’t seal your gearbox on their own.
If every little thing seems typical, try altering the gear-mesh. This is accomplished with the mylar “gaskets” that sit amongst the principal gearbox circumstance and the enter/output caps. Try out introducing or removing some of these spacers until finally your gears have around 1/8″-one/4″ 
of totall
y free engage in. Experts can buy replacements ($1-2) in different thicknesses, but we advise the rapid and soiled strategy of chopping your personal out of a sheet of mylar.
“Groaning”, “creaking”, or “popping” all seem type-of comparable over-the-telephone. The greatest point to do is to disassemble your gearbox and get a look at the gears and bearings. The problem will generally present by itself in the way of damaged/lacking gear tooth, toasted gears (like that image on our property page), or blown bearings.
My Gearbox is Groaning/Creaking: