gear mesh

I replaced my spur and pinion gear is there a special adjustment

Hey, for some reason I stripped 2 spur gears really, really fast. After replacing the new one, the mesh was good I believe at least, very little wobble and I could feel each groove. Then I did one run and looked at it, 1/3 of the spur gear was shredded, that's what caused the clicking noise...

Thanks in advance for any help, I am fairly new to the RC world so go easy on me :) History: My brother gave my son and I a gently used ECX Ruckus 2WD brushless. Everything was stock. We had it out a few times and the 2400mAh battery that came with the truck was not lasting longer than 10-15...

Could bad gear mesh cause the motor to get hot fast? Also how do I know if I'm under geared or over geared?

I have an ECX Torment 4x4 and bought a mod 1 spur gear for it but I'm having issues trying to get any of my existing pinion to mesh with it. I do run it brushless if that helps any...