most likely it is the bearing that surrounds the pinion gear.

another thing it could be, is that all three of those reels are a high speed gear ratio, in which case there is more teeth on the gears, hence the "geary" feeling you r expieriencing.

Solutions--> if it is indeed the bearing, (BNT2170) it could be dry, in which case either re-lubricating the bearing or replacing it, should take care of it.

In my opinion, due to the fact that blades and cranks, put more resistance on your retrieve, it is most likely just the high speed, in the standard Curado, Chronarch, and Castaic, the 5:1 gears will fit straight into them, and should provide more torque, heck, if you really want a reel solely for cranking and blades, throw the Curado B3:8 gears in it, depending on which reel you do this to, you might need to shave the botton of the yoke a bit.

Hope this helps!
Dane