Suggest to add lubricating oil, it can be reduce the friction between the metal gears, also the sound will be smaller when it is running.
Specification:
Item Name: RC Differential Main Gear & Pinion Gear
Application: Fit for HSP, fit for RedCat 1/10 RC Cars
Material: Metal
Color: As Pictures Shown
Main Gear:64T,Pinion Gear:29T
Teeth: 64T&29T
Main Gear hole inner diameter:5mm/0.196in
Pinion Gear Hole Inner Diameter:3.17mm/0.125in
Motor Gear Height: Approx.11mm/0.4in (Motor Gear)
Main Gear:Approx. 9mm/0.4in(Main Gear)
64T Main Gear Diameter: Approx. 40mm/1.57in
29T Diameter: Approx.18.5mm/0.72in
Package List:
1x64T RC Main Gear
1x29T Motor Gear