Proper 2014 Transmisson Eco Diesel Sound?

I have a 2014 eco diesel 1500 Ram and it makes a odd noise when shifting gears when the truck has been running for awhile. My question is, what is the proper sound the shifting of gears should make? do you hear anything? because I hear an almost grinding sound that I'm not used to with other cars/truck.






Thoughts? could I be low on trans fluid or something.


I have almost 20,000 kms or 12,000 miles approx.