Welcome to the forum.
It’s a 3/4” chuck, yes. Thank youHi Zman,
that model is still current (at least outside US if not in it), but I have never heard of a 3/4" collet sleeve. Do you mean 1/4"?
If so, you can get from Ryobi (I got one about 18 months back), but honestly cannot tell the diffence from one that came with a Makita, or a generic sleeve.
You are correct, it is not a 3/4. It is 1/2. Yes terminological inexactitude, lol.Zman, am out of ideas. But I must be missing something. The standard collet is 1/2". Where does a 3/4" sleeve fit? What bits are you using that have a 3/4" shaft? We may be having a problem of terminological inexactitude.