Green Bearing 8.75 Axle Leak

You can get the axle housing seals at NAPA. Part number 15460


So I got the NAPA 15460 and it did not fit. I put it into the the housing and hammered it in but it did not go further in and the axle when put in did not even come close to to fitting all the way in.
Maybe I need to hammer it in further? I'm thinking maybe there is a different size. Anyone have some picture?