What lube are you using? Thin synthetics like 85-120, etc. will let the gears rattle around and possibly cause grinding when downshifting. Use 90 weight mineral oil specified for N-series Ford tractors. Tractor Supply stocks it routinely. It's the same as the OEM trans lube.
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!