need help ! changed water pump and now i have a lube leak 2003 25 hp

[The Arch]

changed water pump and now the shift shaft seeps gear lube how hard is it to change the oring for the shift shaft do i need a special tool any help will be appreciated

[86 inches]

You'll get a better response if you post make, model and SN.

[The Arch]

its a 2003 25 hp johnson 2 stroke basic tiller steer runs good just after i replaced water pump now the shift shaft seeps a lil and i need to replace the seal