I have a 2004 Hyundai Santa Fe 3.5 my boyfriend dropped the transmission pan to check it for leaks when he dropped the transmission pan a little pin right below the shifter arm post popped out and he cannot put the pan back up in there The pin is in the way n won’t push back in..he had to put the car into neutral to get to the bolts on the pan off ,the car has remained in neutral since.. we tried slowly moving the shifter through gears to see if the pin would slide in.any other ideas what the pin is and why it won’t go back in and why the pan won’t go back up and how we can remedy this!

 

Without actually looking at the trans, Maybe a suggestion.
Many times a pin is used to retain the sawtooth shaped link to the shaft that goes into the trans from the outside.
If you try the following it might help,
Is there a hole in that sawtooth/stepped link that rides on a roller and flat type spring? That type set up holds the selector in whatever position selected like drive /reverse.
I'm not positive on this because I can't see exactly what you have. Anyway, if there is a hole in the base of that link apin could be used to hold the link secure to the shaft that goes into the trans. If you move the gear selector and the link doesn't move that could be because the retaining pin might be missing. If that is true just line up the hole on the link base with the hole in the end of the shaft and insert the pin. FULLY , it must be tapped in all the way, tight..
If you haven't solved the problem yet and read this post , get back to me and maybe I can offer some help...