Oil leaks are due to worn of extension housing oil seal and bushing or the speedometer drive gear oil seal and O-ring. The general rule of thumb for these seals is that the repair is straightforward; in most cases, the seals can be changed without having to pull the transmission from the car. The extension housing oil seal is located at the rear of the transmission at the driveshaft connection. If leakage is suspected the vehicle must be raised off of the ground on jackstands securely. A leaking seal will cause transmission lubricant to be present on the front on the driveshaft and dripping at the rear of the transmission. In order to remove the oil seal one has to use the screwdriver or pry bar while being as careful as possible to avoid damaging the splines of the transmission output shaft. If removal is challenging, a further set of special oil seal removal tool might be needed. When fitting the new oil seal use a large pipe or deep socket as a drift to ensure that the oil seal is properly aligned and married to the bore. Before fitting the driveshaft back in, a thin grade of grease should be applied on the splines of the transmission output shaft and the outer diameter of the driveshaft sleeve yoke without putting any pressure on the new seal's lip. The speedometer cable with the driven gear housing will be situated on the side of the extension housing; examine for signs of transmission oil around the cable housing for signs of leakage of the seal and O-ring. Remove speedometer cable connector if available, and with a hook pry out the seal. Last, place a new O-ring in the driven gear housing then put back the driven gear housing with the cable assembly to the extension housing.