A833 getting stuck in 3rd gear

Post a picture of the hub that’s sticking, doesn’t make sense why it would stick in gear unless the hub is wore or linkage is not right.

I am going to try and pull it out tonight or tomorrow. Here is a pick of it when it happened the first time, before I clicked it back. Trans shirts really smooth but for what ever reason it sticks. ’ll try and get a better pic when I get it out. As far as the plug. Not talking about the vent, just a something to plug the tail shaft were the drive shaft slides in so I can get the oil back in it before I put the trans in. I have several automatic plugs but there doesn’t seem to be one that fits this. Thanks guys!

FECAFB07-81A9-4AFF-B4C4-A66B5823E22F.jpeg