TRX4 9 tooth motor pinion

[greenbronco31]

Hello
I installed the 4.75” Proline Mickey Thompson Baja ProX tire (1.9”wheel) and noticed the motor was getting hot way faster than normal. And it’s a cool day where I’m at. So I swapped out my 11 tooth motor pinion for a 9 tooth (dropped the motor down one hole for the correct gear meshing) and it seems to have drastically improved the motor heating issue but now it’s very loud and almost seems to wanna drag more when under a load. Have I done something wrong or am I missing something?
Many thanks

 

[Jerold]

I've tried 9T at one point and it was squealing like a pig. Turn up the volume, it's really annoying. So annoying. Needless to say I ditched the 9T.

 

[nino]

All normal