Yes. If you have the type pump drive that most older JDs have - there are four little plastic biscuits that attach to four steel posts. If you catch in time, all you need to fix is the four biscuits (maybe $10?). If you keep using it - the hard metal parts wear out and then repair costs more. Every time it hammers you're hearing metal parts slamming against metal parts.
YT sells the parts here. I just put some in my Deere 300B.