Have you tried checking the lash with a dial indicator? Sometimes it's not noticeable by the eyeball method. If the teeth are actually running with no clearance, they will be noisy for at least a short time until they wear into a good running fit. The steel gear will eventually force-fit itself to the fiber gear, but that's not the best choice.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!