the advise you get from forums is from people just like you. they are not professionals and the advise is often bad.
there is no specific tool.
the fastest and easiest way is to drill a small hole and screw a small machine screw into the hole and pull the screw to remove the seal.
if you take it to a shop, that is what they will do.
the only other option is to remove the transmission gear set and pull the shift shaft into the case, the punch the seal out from the inside. I would never do that.
further, I have never seen that seal cause a transmission leak unless there is something else wrong, like the transmission vent blocked or restricted. I would check that first.
the only seal I have seen leak on that transmission is the main drive gear seal, behind the belt pulley.
let me know if you need more help.