Did you check the pinion bearing preload after reinstalling the nut? Getting the right torque on the big nut is an absolute must for quiet gear operation and proper bearing life. A drop or two of blue Loctite on the pinion nut thread is also a good idea.
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!