How to Change a Rear Oil Seal on a Ford Inline 6 4.9Lby Don Bowman
The Ford straight 6-cylinder 4.9-liter engine utilizes a one-piece rear main seal surrounded by a seal cover. To remove these seals, the transmission must be removed to gain access to the seal. One noteworthy point -- if the rear main seal has a small leak, such as a few drops on the pavement when left sitting for a few hours, it can usually be fixed without replacing. The seal has simply hardened and with the introduction of a bottle of oil stop leak, the seal will be softened and stop the leak.
Disconnect the negative terminal of the battery with a wrench. Raise and support the truck on jack stands.
Remove the starter with a 3/8-inch drive socket. Remove the shift linkage by taking the nut off the shift lever with a wrench. Take the driveshaft off using an 11-mm wrench to remove the four bolts. Insert the tail housing plug to prevent leaks.
Disconnect all electrical connectors. Remove the bolt in the bell housing that secures the dipstick tube, using a 3/8-inch drive socket. Use the common screwdriver to pry the tube up and out of the transmission.
Remove the flexplate-to-torque converter bolts with a 3/8-inch drive socket. Place the floor jack under the transmission pan and raise the jack just enough to contact the pan.
Remove the transmission mount bolts, using a 3/8-inch drive socket. Remove the two bolts on both sides of the crossmember where they pass through the crossmember and the frame, using a wrench.
Raise the transmission with the floor jack enough to remove the crossmember. Lower the transmission about 6 inches lower than it was on the crossmember to gain easy access to the bellhousing bolts. Remove all the bellhousing bolts with the 3/8-inch drive socket.
Raise the transmission to the point that the rear of the transmission is angled downward slightly. Pull the transmission out, lower it down and move it away from the workplace. Remove all the bolts from the flexplate, using the ½-inch drive air gun and a socket.
Take all the bolts out of the rear crankshaft seal cover using a 3/8-inch drive socket. Punch two holes in the rear main seal with the center punch. Position the holes with one on either side of the seal. Install the two self-tapping screws in the holes. Using the block of wood and the screwdriver, pry behind the head of the screws, alternating sides, so that the seal comes out straight.
Lubricate the new seal with a little oil and install the seal using the seal installer, making sure it is going in perfectly straight. Replace all components in reverse order of removal.