What is this and should I leave it where it is?

here the pic's I said I would take.... they show how the rod SHOULD BE and where it's bolted to the sleeper.
The rod yiu have looks to be missing the end BUT the end may still be bolted to the sleeper if so you may be able to force yhe rod back in to it. If not you'll need a new rod kit (rod and both ends) if so you can take the old rod off and use it to cut the new rod to length then put the ends on and bolt it back together.....

Hope this helps

 

Looks like you might have something rubbing the driveshaft. Electric tape or a bungie.

 

"Let er develop" an old timer used to mutter with a chuckle.

 

The only WORSE RIDE is dropping the Rear Frame Suspension Air Bags and "realizing such about 15 miles later".

 

That controls the amount of air in you cab/sleeper air bags. Do your sleeper air bags have air in them?

 

Might want to spray a little paint on that witness mark on the shaft to help camouflage it from the eyes of an inspector and keep it from rusting.