One day I switched my 32P spur gear to 0.8M but not the pinion.
I noticed 32P RCM pinion and 0.8M traxxas spur gear have more grinding noise than 0.8M RRP pinion and 0.8M spur gear.
32P vs 32P gears run smooth as silk but not 32P vs 0.8M.
I checked the mesh and they are both fine.
I never thought the tolerance between 32P and 0.8M can make such difference.