Keyless Chuck Repair

[f350ca]

I was gifted this keyless chuck by a friend, it had been sitting a long time and was stiff, I tried washing it out with WD40 then giving it a generous flood of light oil. Helped a little but is getting stiffer as I use it.
Think it needs to come apart for a through cleaning and possible derusting.
Searched the net for instructions on disassembly, but found nothing.
The ring at the top comes off, had it off it to use wedges to change the JT shank for this R8
Its a Metabo Futuro 3-16
3 to 16 mm or 1/8 to 5/8 capacity
Anyone know how to get it apart before I start pressing in the wrong spot,


Thanks