Warn 9790 manual hubs on 1993 F-150

I am trying to install Warn 9790 manual hubs to replace the automatic hubs on my 1993 F-150.

I have removd the old hubs but the Warn hubs will not slide in far enough for me to install the outer snap ring.

I'm assuming that I need to remove the inner retaining ring and spacer that is still on the splined shaft. My real question is how in the ^&$% do I get the inner retaining ring off (It's like a heavy C-Clip)

Thanks in advance for you help!