Late 30s Gruen Time Setting Issue

[offrdmania]

I have a late 30s Gruen doctors watch that was passed down to me by my grandfather. It was tastefully restored and serviced a few years back.

I only wear it on very special occasions and this previous occasion, when I went to set the time, I could feel slippage.

I pulled out the crown to set the hands and could feel the slight resistance from the hands turning but then all of a sudden, the hands would stop and that resistance was gone. A few more turns of the crown and the resistance returned and the hands would move again, only to stop a few turns later. It is as if it catches and then slips.

It is a manual wind movement.

Let me know your thoughts