This procedure also applies to the transfer case extension housing seal on 4WD models. Oil leaks at the extension housing oil seal are usually caused by a worn seal lip, and replacing this seal is relatively easy since it can be done without removing the transmission from the vehicle. The extension housing oil seal is located at the rear tip of the transmission extension housing, where the driveshaft is attached. For 4WD models, there is no extension housing, as the transfer case is bolted to the rear of the transmission housing, but the procedure for replacing the rear seal is similar. If a leak is suspected due to puddles beneath the extension housing seal or consistent lubricant loss, raise the vehicle and support it securely on jackstands. A leaking seal will cause gear lube to ooze or drip from the rear of the transmission, coating the forward end of the driveshaft and leaking onto the ground. Remove the driveshaft or transfer case for 4WD models. Some seals have a metal casing with a lip, which can be pried out using a chisel and hammer; care should be taken not to damage the splines on the transmission output shaft. If the seal lacks a metal lip, a special oil seal removal tool can be obtained from most auto parts stores. To install the new oil seal, use a seal driver or a very large socket as a drift, ensuring that it is driven into the bore squarely and completely seated. Finally, lubricate the splines of the transmission output shaft and the outside of the driveshaft yoke with lightweight grease before reinstalling the driveshaft, taking care not to damage the lip of the new seal.