727 rear band pin fell out!

Hi all!
Last week a really wierd thing happened to me. Rear band pin fell out of my 727 so I lost reverse and like 30% of oil from the gearbox. All underbody and rear axle are covered with trans fluid...
Can anyone tell me if this just happenes sometimes or someone before me screwed something up?
I found the pin on the sreeet a day later near giant trans fluid stain. Pin had just one o ring on it, one was missing.
After removing the pan I found all the missing parts plus detend ball from the gear lever out of valve body.
Turned out that gear lever was very loose so detent ball fell out (also this is why I had problems starting the car in park). I spot welded the selector piece to tubular part fixing detent ball problem.

My question is: did any of you guys loose a pin???
Coud this have happened cause I went from 3rd gear to 2nd to help myself on the braking (emergency stop)?

I already put everything together, just waiting for new filter so I can put new oil in the trans and get the car back on the road.

Aslo wanted to make sure about adjusting rear band lever.
How many Nm should I use how many turns back with 4.2 lever?
I used 8Nm and 2 turns back, is that correct?

Two turns back with a 4.2 lever. 8 NM is as close to 72 inlb as you can get.

I believe that pin is held in with the tailshaft. If someone ground the little area off the housing then the pin would fall out. You may have to source another tail housing or it would keep popping out.

While I was locating a photo, 80fbody beat me to it. There's no way that pin would have come out unless the retaining "finger" in the tail shaft housing was missing. In fact, it only partially covers the pin, but retains it, nonetheless.

If you can slip the pin back in the case right now, then there's something wrong with your tail shaft housing.

Yes, apparently someone cut this piece out.

As for getting another tailshaft housing, it is close to impossible as I have the car in Europe in Poland. Getting anything is pain, simple things like filter for 727 I need to import from the States, so this is 15-20$ for the filter and 20$ for shipping...

I will make a bolt on piece that will hold the pin, will use 2 longer pan bolts in this place. This is as simple sollution as I can think of right now.

There is no pressure on that pin ... Use the tail housing bolt nearest to the pin with a piece of flat metal bar with a 3/8 hole for the bolt and bent it to cover the pin bore.
Use a small amount of silicone on the pin Oring to aid in the sealing.