2010 Transmission not shifting?




Have noticed that when I drive down an inclined road at 30 MPH, transmission drops to very low gear and sometimes does not seem to shift back to a higher gear. Engine braking???
I live in an area where all nearby streets are 30 MPH so that may be highest speed I drive for a few miles.
Also, is there any way to tell what gear car is in? On my 2010, the display only shows D when in forward gear. Have played with paddle shifters, but that shifts it down or up a gear. Guess I could assume I was in a different gear, but not sure.
Thanks


