Disconnect the cable that carries power into your battery from the battery's negative terminal. Rise your vehicle up using jackstands, then hold it firmly in position. Remove the skid plate, if equipped. Drain the transfer case lubricant. Remove the front and rear driveshafts. If you have a Frontier or Xterra, take out the torsion bars from the front suspension. Take all electrical plugs off and disconnect the transfer case vent hose from its top. Rest the vehicle using a floor jack while adding wood under the jack's head to distribute the weight evenly. Secure the transfer case using a jack made for this job, then add security chains to keep it steady. Lower the jack holding up the transmission mount from the cross member, then take off the cross member. Loosen both jack supports for the transmission and transfer case until you can easily reach the upper bolts. Take out the transmission-to-transfer case bolts. On some models, you'll find two different lengths of bolts, so keep track of them during and after removal. Check once again that all transfer case wires and hoses are removed. Then slide the transfer case towards the back of the vehicle, keeping it level, until the transfer case clears the transmission. After you've cleared the input shaft, move your transfer case away and take it out from underneath your vehicle. To put back the transfer case, we add sealant to where it connects to the transmission, put bolts on the transmission to the transfer case, following correct bolt locations and bolt tightening guidelines, refill the transfer case with needed fluid, and for our Frontier and Xterra work, we put back and adjust the torsion bars.