Anything like an old long, wide-blade screwdriver with a 90 degree bend to it with the bend being about 1/4"-3/8" should get into there to remove the seal. I made such a tool from an old sturdy screwdriver, heating the blade with an acetylene torch, and bending it in a vise, to 90 degrees. Remove the push rod, place the bend into the space where the rod was, push it sideways towards the outside circumference of the seal, and give it a quick, short yank. When working with seals several inches in diameter, if a traditional seal-puller won't work, because of space constrictions, you may-need to reposition the puller at several locations around the circumference to pop it loose. When I say, 'circumference,' I am not referring to prying around the outside edge! You pry from the inner lip.
New seals are usually inserted dry, use a socket the same size of the outside diameter, with a socket extension, make it as-square as you can, to drive it in. Light taps should be used, no-need for much force. If it doesn't start evenly, re-position it and do it again. Some people like to use the old seal as a driver for the new seal, but I have more-luck with a socket of the correct size, and patience.
Don't forget to use some lube of whatever is being sealed inside, on the lip of the seal, where the shaft comes-through. Failure to lube the seal lip will result in premature failure of the seal. I've seen differential pinion gears with grooves in them, on their shafts, where the seal rubs.