Please add the lubricating oil, it can be reduce the friction between the metal gears.

The Diff Gear Motor gear and drive shaft drive gear set designed for center drive shaft
Compatible with WLtoys 144001 124016 124017 124018 124019 1/14 RC Car.
The 144001 gear set made of high quality steel,heavy duty and durable to use.
A great replacement gear set for WLtoys 144001 124016 124017 124018 124019.
Easy to install and replace.

Material: Steel.
Reduction Gear Teeth: 44T.
Pinion Gear Teeth: 27T.
Pinion Gear Inner Diameter:3.15mm
Drive Shaft Drive Gear:12T;
Bearing Size:11x7x3mm
Color: Black.
Weight:48g/Set

Package Includes:
1x Reduction Gear 44T
1x Pinion Gear 27T
2x 12T Drive Shaft Drive Gear
4x Bearings
1x Screw Set