Will not neglect to re-seal the gearbox with RTV soon after you’ve found the correct mixture. Even even though they are known as “gaskets”, they won’t seal your gearbox on their personal.
If everything appears normal, try adjusting the equipment-mesh. This is done with the mylar “gaskets” that sit among the principal gearbox 
situation and the input/output caps. Attempt including or removing some of these spacers till your gears have around 1/8″-one/four” of totally free engage in. Pros can purchase replacements ($one-2) in different thicknesses, but we recommend the fast and dirty method of cutting your personal out of a sheet of mylar.
“Groaning”, “creaking”, or “popping” all sound type-of comparable in excess of-the-phone. The greatest issue to do is to disassemble your gearbox and consider a look at the gears and bearings. The situation will typically existing alone in the way of damaged/lacking equipment tooth, toasted gears (like that picture on our home web page), or blown bearings.
My Gearbox 
is Groaning/Creaking:
rotary cutter gearbox changed my life right!