This procedure also applies to the transfer case extension housing seal on 4WD models. Oil leaks frequently occur due to wear of the extension housing oil seal, and replacement of this seal is relatively easy, as it can be performed without removing the transmission from the vehicle. The extension housing oil seal is located at the extreme rear of the transmission, where the driveshaft is attached. If leakage at the seal is suspected, raise the vehicle and support it securely on jackstands. If the seal is leaking, transmission lubricant will build up on the front of the driveshaft and may drip from the rear of the transmission. Remove the driveshaft. Using a chisel and hammer, carefully pry the oil seal out of the rear of the transmission, taking care not to damage the splines on the transmission output shaft. If the oil seal cannot be removed with a chisel, a special oil seal removal tool, available at most auto parts stores, will be required. Using a large section of pipe or a very large deep socket as a drift, install the new oil seal, ensuring it is driven into the bore squarely and completely seated. Lubricate the splines of the transmission output shaft and the outside of the driveshaft yoke with lightweight grease, then install the driveshaft, being careful not to damage the lip of the new seal.