The I&T FO4 manual has a pretty good step by step for splitting.
If you don't have that manual I suggest you get one.
If you do have the manual, read the section on splitting a couple of times before you start.
First of all drive a wedge in on both sides of the front axle so it doesn't roll sideways.
I like to block up the engine half and use a floor jack to roll the rear half away from the front. Easier to roll the back half than the front.
I do not like jack stands for working on tractors.
I prefer wooden cribbing like is in the photo. Much safer. If you don't have wood cribbing go to Home Despot and pick out the crookedest, most twisted 6"X6" in the pile. Throw it on a cart and push it to the front and ask the manager to discount it cause it's so crooked. Don't tell him what you want it for. You'll get it for about 1/2 price. Then take it home and cut it into 2' pieces.
You are wise to replace the tranny input seal. Also inspect the ring gear for excessive wear while you are in there.
Just take your time, read the manual and it is actually pretty easy to do a split. I have always had good luck buying parts from YTMAG. I like to support our hosts who provide this free site.