Under-Sink disposal unit jamming. A lot.

[Bimwad]

I had the same situation with a similarly-aged disposal and concur with the others, it's time for a new unit.

There are only two major manufacturers of disposals, and one (Insinkerator) has an overwhelming share of the market, so there is a 3-in-4 chance that the new one will be a straight swap for the old one.

It's an easy job, just disconnect and dismount the old one, then mount and connect the new one. Don't need to mess with the flange.