The snap clip won't fit in even with clip pliers because there is no room and nothing will move.
Does the whole cam assembly needs to be pulled to get the clip in.
This is the shaft assembly inside the cam assembly.
One of your bearings is not pressed all the way to the fatter center part, or the shaft assembly is not pressed in to the stop in the cam assembly where the pulley is.
Yes the whole assembly comes apart easy out the sprocket side if you have a bearing press.
I changed out the standard output shaft in two 4G's with 2 of my designs.
The first shaft is a bit longer and keyed it's entire length so you can put the output sprocket anywhere you want.
The 2015 Grube 10G's will have this standard.
The other is a 110mm long shaft for direct jackshafting.
Your bearing is just not pressed in far enough to get the clip on.
It is best to take the cam assembly out but to do it but you have to take the 100T off, and to do that you need to take the 20T as that pulley can slide off with the belt on it, the 100T can't.
This is a pain in the butt but you might be able to fix it in place.
Take the sprocket off.
Brace the base (not the pulley) and with a piece of wood on the end of the shaft give a couple good whacks to make sure the pulley side bearing is seat against the cam assembly.
If the sprocket side bearing didn't follow in...
Get a washer or heavy chunk of steel as wide or wider than the bearing with a hole for the shaft to go though.
With a long socket for even pressure you can press (or hammer) the bearing the rest of the way in and clip it.
You need to press BOTH edges of the bearing, not just the inside or outside or you'll compromise the bearing.
DO NOT use the pulley as leverage, hold just the base as that pulley can bend pretty easy!