The transfer case is an integral component of vehicles. It transfers power from the transmission to the front and rear axles via the driveshafts. The transfer case also synchronizes the difference between the rotation of the front and rear wheels so that they rotate at the same speed. 

If your transfer case goes bad, you might have problems with shifting gears and your 4-wheel drive system starts to act up. To maintain the transfer case in good condition, the transfer case liquid must be changed every 30,000 miles. In case you have vehicles for towing, you should replace the liquid more often.