How do you replace the rear main seal on a Ford F-150?

Answer 1

Every F150 I've had (7 total) from 82 up had one piece seals.

The first thing you have to do is access the seal. That means removing the transmission, bellhousing, clutch or converter, and flywheel or flexplate. After that you have to determine if your seal is a one or two piece. If it's a one piece, the change is simple. Ply the old seal out. Be careful and take your time. You don't want to damage the sealing machined surface of the crankshaft. After the old seal is out, grease the sealing surface of the new seal. Install the seal evenly and slowly so as not to cause distortion.

If you have a two piece seal, you'll have to remove everything previously listed along with dropping the oil pan. Next you'll have to remove the rear mail bearing cap. From the cap remove one half of the seal. Be careful not to drop the cap or damage the bearing. Install the new half in the cap being sure that it is fully seated. If done properly you'll have excess seal sticking out at both ends. Trim them off and set the cap off to the side. Next you'll need a tool called a sneaky pete. Follow the instructions and remove the old seal that is still in the engine block. Install in reverse and trim as with the cap seal. Next, dab a light coat of silicone sealer on the ends that you trimmed on the cap and reinstall the cap to the proper torque. Or just sell the truck.

A one piece seal requires the transmission or engine be removed, a 2 piece seal is accessed by removing the oil pan, only, which may require the engine to be lifted off the mounts enough to let the pan free. This job is not an easy DIY, driveway job, and should be done by a reputable shop. It is easy to go to a parts store and look at the seal for your vehicle and see which one you have.