This old boy has certainly seen better days...
But that's a nifty ball type grease fitting
Notice, no 'quick release' button
and notice, no part number like they all have now.
I've been denied a warranty on an old Craftsman tool before because of that lack of part number. They'll usually let me go right in and pull the tool off the shelf. As long as it has the same number, they swap it right out. But when there's no number...
This one is in a bucket of other craftsman tools that need replacing. I'll try to get it replaced one of these days. I don't know if I'll try to fix it if they deny it though.