Hey. I had this weird ordeal the other day where I temporarily got stranded.

I was going up a huge hill and the transmission would slowly get out of gear and into neutral. After I beat the hill and was on the other side, the transmission must have gotten really hard and I couldn't get into gear at all. I pulled onto the side of the road and waited. After 10 minutes I got back into gear, but after 5 more minutes of driving it got hot again and went into neutral.

I don't know how or why it's doing this and there are no trouble codes. Well I got an fuel cap code but it went away.

 

Could be low on fluid or it could be a trans fluid pressure issue which could be caused by a bad solenoid.

Hows the fluid itself look? Pink, dark red, or brown?

 

Hopefully it's just low on fluid... Otherwise there's a good possibility a rebuild is needed..

 

Something to check

I have changed mine in an around 35 to 50K as a rule. I have one vehicle that you cant even check the fluid level in the thing is sealed so you have to have a Garage change it out in that case they recommended 100K it had 104K when I finally changed it out. Mostly cause of my travels. it had the same actions as you have described. Changed it out and it works fine now.