Maybe I overdid it a little......
but at this point I would say its "bulletproof" aside from the structural strength of the case itself.
I let it cool in a bucket of oil.

 

Interesting - thats pretty rare to see on these transmissions. I assume this is for a track only drag or oval dirt car?

Whats the rest of the setup (power)?


TBH theyre pretty bulletproof stock too. Some of the quickest 60' FWD Wbody cars were done on a totally stock diff.

 

No no it's not anything special. Just my daily. NA 3.8l SS just got brand new rings. Runs nice. Still needs a tune for straight pipe. The only thing really special I did was rebuild the trans with all the Sonnax upgrades to the valve body , transgo shift kit and of course new clutches , seals , molded pistons etc.. The works you know. But this last part is what got me. See this roll pin sheared.


This crosshaft started spinning. The only thing holding it in is the case which has a nice groove in it.



And these were chewed.


Maybe the gears locked up and it's the other way and this is a bad idea. Because I've had a differential explode before in a truck and it shot a chunk of gear clean out the diff cover. ****.....

 

Looks like you got pretty lucky on catching that broken roll pin early. Ive seen some rather nasty failures from that breaking and the cross shaft sliding out until it makes contact and chews the case up (of course sending aluminum shavings into the pan in the process) over time. Sure can make a huge mess.

If I remember right, the reason for them breaking is from the spider gears running dry on lube, so they try to weld themselves to the shaft (scoring it in the process) which causes it to spin in the carrier and break the pin. Some of the aftermarket rebuilds add a diff squirter to help add lubrication down at that end too. Ive seen some of the aftermarket LSDs through the years use various methods to address this as well either via a lube slot cut into the shaft and/or using a harder material for the shaft (the prevent the scoring from starting in the first place which increase the desire of the spider gears to grab the shaft vs spin freely on it).


Edit - I thought you'd actually welded the gears together making a 100% locked diff. Looking at the pics again though, it seems like perhaps you just brazed the area by the pin to keep it from breaking again?