Shimming Spinning Reels

[steelfish]

.......one thing I noticed in my shop years ago was a strange phenomenon of a reel that was smooth before service becoming rough after service. Some techs back then told me they thought the gears just needed to reseat themselves and would smooth up over time. That wasn't acceptable for me to do with customers reels. I either needed to figure a way to be sure the reels would be at least the same smoothness after service as before, if not better, or just quit doing spinning reels altogether...

been there and thought the same !! 

and hate it!

[boon]

In terms of re-aligning gears for meshing, the gears are almost certainly "hunting" in any modern reel; that is to say the number of teeth on each gear is usually a prime number so there are no common factors, and your "5:1" reel is probably more like 13:67. This means that every tooth of the drive gear will eventually meet every tooth of the pinion gear, and the position the gears are in when the reel is reassembled means nothing.
The exception to this is gears that have to be "timed", such as the oscillation drivetrain in Shimano Baitrunner/Thunnus reels, because the oscillation gears aren't round and thus need to stay in relationship to one another.