Stuck in 2nd gear, but got unstuck
 

Driving around today I had to stop abruptly, then put in reverse to back up to finish U-turn.
Anyways, afterward transmission got stuck in 2nd gear. It would still go to neutral and reverse and function properly. But when put in gear it would start with 2nd gear and never get int 3rd or downshift to 1st.
Then I decided to try shifting manually. Went into 1st, shift to 2nd and "guess what"**** into 3rd and OD. All of the sudden everything works fine. It downshifts and upshifts fine.
What could be a cause of this?
Transmission is a rebuild (upgraded) 46RH.

Linkage problem? Sticking valve? Phase of the moon? High tide? :D

If it continues to work right, chalk it up to a fluke, and call it a day.

How many miles on the rebuild?

No more than 10k miles on rebuilt
Yes, that is what I thought, a fluke. One of those unexplained mysteries :)

If it happens again, I would become concerned. :) If you have warranty left on the trans, might chat with the rebuilder, and see if they suggest anything.

one thing heyyou has showed me is that these trannys love to raise the hair on your back for no reason. mine went into limp all of the sudden the other day and all i did was reset the pcm and its been fine ever since. If these things fail, your gonna know it, like he said call it a fluke and if it doesnt happen again call it a day. heck a few months i noticed mine was idling weird while i was closing my gate and when i went to look my oil pressure was like at 10 and then the truck died. so i got back in and started it and drove off and it never did it ever again. I've learned to worry about things more on these trucks as they become consistent failures excluding maybe brake failures haha. let us know if it does it again.