Hi, Pull the pan, and remove the rear main cap. Using a dowel or suitable pusher, from one side, push the upper seal out from one side, and pull it out with pliers when you can get a good hold. Bottom part of seal is easy. Some people use wire pushed through the top area, tied to the seal to pull it through. Pull the wire, and push the seal to get the new piece in. Also push the upper seal in on the sides (I use a medium small screwdriver ) so it doesn't get thin. Not the best, but it works. Leaks can be caused by Loose bearings too. SOMETIMES you can get molded rubber replacements, MUCH easier to install. Loosening all the mains will make it easier to install the upper part of the seal. Not too much, 1/8 " approximately. Good Luck.