Going through the spare parts the other day. Found this Ring gear... wondering what would cause it to crack like this??The crack runs right along the base of the tooth.
I torn down rear where the ring gear came off in 3 pieces. The only thing keeping the ring gear in place was the bolts. Couldn,t even see the cracks until it was unbolted from the carrier.
Likely the same forces that cracked this drive shaft end under the pinion gear nut.
The rear axle takes all the loads from hard braking, to getting under way and to sudden reversing too. Lots of forces to make things crack or come apart!
I had an axle shaft that had a similar crack that ran all the way from one end to the other. I did some hard braking some years before discovering the crack. During that particular hard stop, I heard "CRRRACK". I thought, OH S#$T! But, afterwards, everything seemed o.k.. Drove the car for several years after that, then finally took the rear end apart for other reasons and found the cracked axle. It probably split along a seam, (defect), in the metal that had been there from day one.
As for the ring gear, it could be from a hard stop or piece of junk that "got between", or maybe a heat treat quench crack. Whatever the cause, I suspect it's no longer in your spare parts pile .
Maybe he left out the u-joint pin.