Removing Oil Pump Drive Gear

[Spln_Hrd]

I am wanting to replace the gasket (O-Ring) directly behind the sprocket but can't seem to get it to slide off. I've pryed and pryed with no luck, I have removed the gear casing on the back side of the front cover and the front cover is out of the car any pointers would be highly appreciated.

Thanks Everybody!!!!!!

 

[Spln_Hrd]

P.S. Without using a gear puller, if at all possible.

 

[Spln_Hrd]

Just in case someone stumbles upon this thread via search. I used a punch on the end of the shaft (stud) and hit it with a hammer and it finally freed up. This engine has sat for several years so thats probably why mine was so difficult to remove, in the past I have been able to slide them off by hand.