Hard to say..
I've seen more than a few rear diffs with teeth chipped on ring gears ,spiders gears,etc,during routine 90W gear oil changes!--found them stuck to the magnet epoxied to the housing!...along with wheel bearing rollers,tons of metallic sludge--
One was a 1979 Chevette I delivered auto parts in,I decided to change the right rear wheel bearing that was noisy for 2 years one slow day at work..two ring gear teeth were stuck to the magnet,and it was not just a "chip"--theese were nearly the entire teeth!--and I never heard any noises from the ring and pinion,just the defective wheel bearing!(which caused the ring gear teeth to break,a few rollers went for a ride thru the ring and pinion(pinion was perfect!--)..
I told my boss,he looked at it,and said "well,just put it back together,and drive it!--if it goes,we'll get another rear end from the salvage yard and have it installed"....I drove that car another 15000 miles before I quit 2 years later,and it only had a very slight "thud thud thud" when you coasted downhill..it never broke or got any worse!....
On the other hand,I had a "beefy" 12 bolt snap the pinion right off,when I got mad when the truck kept stalling in the cold due to no choke--I got the rpm's up to 2500 or so and put it in drive--got about 3 feet,and I heard a big "CLANG" and the driveshaft started beating the underside of the bed to death!...no more pinion shaft!...the one and only 12 bolt I've seen break too!
So its a toss up--after all the ones I saw with "shrapnel" in the magnet that made no noise,and would likely have gone undetected if not for the oil change,it makes me wonder whats in MY rear axle!--I dont think I wanna know!....It might last a long time,or crap out in 5 miles--its anybodys guess!..but one thing for sure--it WILL break!!--its WHEN thats hard to tell!..
