To change the seals on a driveshaft, first dismount the correct driveshaft. Carefully use a large screwdriver or suitable lever to prise the oil seal out of the transmission casing ensuring not to damage the casing by using a piece of wood for protection. Clean out the oil seal seating in transmission casing and then apply a little general purpose grease to the new oil seal lips and push it part way in the casing by hand, making sure it is square to its seating. Use appropriate tubing or a large socket to force the oil seal all the way into position until flush with the casing edge and fit up the driveshafts. For the input shaft oil seal, take out the transmission together with the clutch release bearing/slave cylinder. Note the fitted depth on the drill a small hole on the hard outer surface of the seal and insert a self-tapping screw, and by pliers to extract the seal. Lubricate the new seal with grease and fit with the lips to the bellhousing with the lips towards the gearbox side, using a deep socket or suitable tubing to seat it. Finally, re-fit the release bearing/slave cylinder and the transmission.