just went through a rear for a 58 chevy that was like that. the car had a 3:55 in it and my buddy wanted to use a 3:36 that he had rebuilt because the 3:55 was leaking at the pinion seal and was a tad noisy.
the 3:36 had several gears that had some slight pitting, and he was worried they might "sing".
put that rear in, works great, no noise, and decreased highway RPM as a bonus. this car is a cruiser and will not be raced, but his rear [pun intended ] will last for a long time.