This is the epoxy putty that one can easily buy at the market.
A gel-type epoxy can be also used.

Massage the epoxy putty with the hand and mix it.







Do further work after the putty is completely applied and dried.

The Differential Gear acts to absorb the pressure from the tires
of the car when it is going through a corner.
However, this is usually locked because all four tires can use the
same pressure/power to drive better during rock crawling.