833 aluminum overdrive reinforcement

Unless the transmission has been beat on hard with many many miles don't fret it.
Take a look at the cluster shaft pin bore for signs of hammering. It don't hurt to look at the schyncro's also for signs of a driver that never let's go of the shifter. Most show no wear that I have picked up.
I have also treated them very mean on the street behind mild 440s and never ever broke one. Not a single one not even the aluminum cased ones.
I know there are guys that say different on the site here but this has been my experience
with the overdrives. Nothing to worry about.
Your rear axle will break first. I have broke every single 8 3/4 I had ever used until the day I had to give up on them as they were getting harder to find and I got costly to replace them.
Dana = problem solved. But likely would be overkill with a 360.