Strange transmission problem

[TopNotch]

This evening I fixed a strange transmission problem on my yellow car. The other day as I was driving to work, I couldn't get into 5th gear or reverse. So after work, I pushed it out of the parking place, and drove home in 1st-4th. I took of the select cable and determined that the problem was in the transmission, not the shifter.
This evening I had time to check it out. First I took the control box off my old transmission, which still sits in my garage. Having never messed with a transmission, I wanted to see how it worked.
Then I took the control box of the transmission in the car to see if anything was different. And I found a little piece of plastic in the transmission where the "tongue" from the control box fits, which was preventing me from moving it to the 5th-revese plane. How it got there, I don't know, but it had red paint on it, and if you read my previous thread about replacing the transmission, you know that my "new" one is painted red.
Anyhow, I cleaned up the control box from my old transmission, and put on the one in the car. I can shift to all the gears again.

[GTRS Fiero]

At least you didn't have to pull the transmission.

What did you do with the control box you took off the "new" transmission?  I'm curious if you could compare notes with someone else.

[TopNotch]

I put it on the old transmission, just to keep it from being loose. What do you want to compare it with?

[GTRS Fiero]

Not I, but it seems that most everyone else has a manual transmission.  I think Dave just picked up one.  Perhaps he could compare his, to look for that part.  Isn't that control box basically sealed?  Foreign objects should be denied entry.  It seems that that transmission ran fine for 7 months.

[TopNotch]

The box is sealed. My theory is that some kind of repair was done with epoxy (can't figure out what, though), which eventually broke loose and fell to where I found it. (Not JB Weld, but regular epoxy -- that's what it looked like.) That's one reason why I used the other control box. I also didn't like the fact that the red paint was flaking off. BTW, the transmission is an Isuzu.