Hard to completely diagnose over the internet - but I'd be willing to bet you have a worn Line Guide Pawl. It's a small part that usually causes this kind of malfunction in a reel (slightly binding, clicking during retrieve, etc....) If you let me know the exact model number of the reel, I can look up the part number for you. Or you can go to a website like Mike's Reel Repair and look at the schematic for that particular model:
http://www.mikesreelrepair.com/schematics/thumbnails.php?album=8
Very easy to replace. Just unscrew the Pawl Cap, tap the reel a few times until the old Line Guide Pawl and spacer come out, put in the new Line Guide Pawl, stick the spacer on top, and then put the Pawl Cap back on. Really easy.
You can check by unscrewing the Pawl Cap right now and dropping the Line Guide Pawl out. The little grove is probably very worn. If there are no broken pieces, you can probably safely just put a new one in. If broken pieces are obvious, then you should take it apart and clean out the Worm Shaft and Level Wind Guard before putting a new one in.
Worm Shaft cleaning - do that with a old toothbrush. Make sure you clean every groove.
Level Wind Guard - Q-Tips work extremely well.
Hope this helps.
All the best,
Glenn
