Looks like one is teflon & the other viton.
To do this job correctly, you'll need a crank hub puller , a crank seal install tool (you can probably get away with not using this), and a flywheel lock . Of the three, the flywheel lock might be the most important, since I don't know of a better way to lock the engine in place without screwing up the ring gear.Still need some direction here...I hear that I have to have a 27mm socket and a cheater bar on the ratchet to get enough torque. I am doing this on the ground, do I need to get it raised up on jacks a bit? What do I hold the hub with? (is "hub" what it is called?)