All the broken or damaged 8 3/4 axles I've seen or heard of all twisted the driver side axle spline at the end of the splines nearest the brake backing plates shruggy I have broken two 8 3/4 axles at that point also shruggy
Mopar rolled those splines on those axles, they are not machined like race axles are scope

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)