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.

The Transmission Gears Compatible with /10 2WD Slash VXL/ 2WD Bandit VXL/ 2WD Rustler / 2WD Stampede RC Car.
The 2wd slash gears made of #45 steel material,greater strength and heavy duty.
Easy to install, great for replace the old or broken part.
Increase overall performance and durability of your RC car.

Item Name: 54T Main Gear & Pinion Gear
Material: Steel
Main Gear:54T;
Pinion Gear:16T 18T 20T ;
Main Gear hole inner diameter:11mm;
Pinion Gear Hole Inner Diameter:5mm
Weight:70g/Set

Package List:
1 x 54T Spur Gear
1 x 16T Motor Gear
1 x 18T Motor Gear
1 x 20T Motor Gear
3 x 3.17mm to 5mm Shaft Converting Adapters