I refurbed mine some time ago. Not sure exactly what you are asking, so posting this diagram:
That looks like the locking pin.
I don't think from memory, you do anything with that collar.
It's the 'indent' that the ballbearing locks into so that you have to push against resistance to get reverse and first gear.
Ball bearing and spring also shown in pic.
Someone may correct me. That's my recollection of it anyway.