I believe those gearboxes are packed with grease, which can dry out over time. It's possible but I would doubt it if you bought it new a few years ago? Pretty sure you can open them up, clean the dry grease- which is probably caked on the side of the housing and not in the gear splines- and repack the grease. But I have never done it on my Jiffy, pretty sure it hasn't been in it's 10 year or so life.
