The construction of the Toyota Engine and Motor Mounts are a combination of metal and polymer. This allows for them to be flexible and still remain securely attached to the frame of the Toyota.
There are a total of three engine and motor mounts on the power plant under the hood of your Toyota. There is one on each side of the engine near the front of it. The last engine and motor mount is located near the rear of the transmission and is centrally located on it. The reason for this configuration is so the twisting and turning of the engine from the torque it is created is countered in a balanced manner.
If your vehicle did not have any engine or motor mounts holding the power plant in place, the engine would literally jump out of the vehicle due to the extreme amount t of twisting power generated by the torque the engine is generating. This is the same type of result when one or more of the Toyota engine and motor mounts fail. The failure is generally in the polymer section of the mount that has given into the ravages of time and force that has been constantly exerted against it when the vehicle is being used.
The only preventative maintenance that can be done to help prolong the lifespan of the engine and motor mounts is to keep the engine compartment, including the lower sections of the engine, clean of oil and grease. This will not only help the mounts to last longer but make the Toyota engine easy to work on without the technician getting really dirty from all of the excessive fluids that have leaked from the engine.