Transfer case or torque converter?

[Bobs Big Blue 92 4wd]

I suddenly lost all gears no warning or signs at all! Truck sat 5/6 yrs and was drove occasionally until 2 yrs ago. I got it up and going and lubed up everywhere I thought necessary. 1 thing this is my first 4wd, and transmission always worked fine or so I thought. Never searched for gears, or anything out of the normal at all.
I took a turn off the hwy and lost all gears and devolved a whining noise at the same time.
I flushed transmission fluid out of line to cooler to avoid mess. Then dropped the Pan and discovered a stripped and rtv filled bolt hole. I fixed the bolt hole and cleaned everything up before reinstallation. And replaced the filter while there hoping it was bad fluid and the sharp turn made it slosh. That's not fixed it of course.
I then dropped the fluid from transfer case and a small bullet looking internal part fell out into the drain pan (part pictures below).

So my question is: Did the transfer case fail or is it the torque converter? Or both? And: Can I fix it in my driveway under my shadetree?

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[Keeper]

I have no idea what that part may be, but here's another possibility.

The floor shifter may have just slipped into neutral. I had a dog once who would constantly knock the tc shifter as he was farting around in there. The shifter wouldn't immediately shift out of 2hi and into neutral, but sometime later it would do it, and it was always on a turn. Took me quite a while to figure out the original k9 source of that "problem". Ended up putting a floor console down there, which I love btw.

 

[Bobs Big Blue 92 4wd]

Went back out and started pulling transfer case. Cause I'm pretty sure it's doneski, and found this spring that fits inside perfect but wasn't in the drain pan?? Laying on the tarp I'm rolling around on. 113° heat index makes it really tough to go too hard too long.
If anyone has a transfer case for sale let me know! Idk if i can ask that here?

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[zitkada]

Went back out and started pulling transfer case. Cause I'm pretty sure it's doneski, and found this spring that fits inside perfect but wasn't in the drain pan?? Laying on the tarp I'm rolling around on. 113° heat index makes it really tough to go too hard too long.
If anyone has a transfer case for sale let me know! Idk if i can ask that here?

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I believe that is the "Shift Detent" and spring, somehow it got knocked out of place. Is there excessive play in the "Shift Detent Lever"?

 

[Cadillacmak]

Went back out and started pulling transfer case. Cause I'm pretty sure it's doneski, and found this spring that fits inside perfect but wasn't in the drain pan?? Laying on the tarp I'm rolling around on. 113° heat index makes it really tough to go too hard too long.
If anyone has a transfer case for sale let me know! Idk if i can ask that here?

What year and make is this truck?