What is this tube?

[Dragoon2]

I recently bought a 2017 RAM 3500 with the 6.7l cummins and this tube is leaking. What is it so I can get it replaced. Also, since it started to leak, the truck shifts poorly.

 

[Gear Jammer]

That looks like the exhaust pressure sensor, it shouldn't have any liquid in it, just exhaust gasses. I don't know why it could cause your trans to shift different though.