2014 SR5 owner here too...
I have found that there is a specific process to putting our trucks into 4lo...
to answer your question, yes, its normal.
to do it right, put the truck into neutral, foot on the break. then put it into 4lo, then into drive or reverse...any beeps should stop, and you should see a bunch of icons light up on your speedo dash. one thing you may need to do is press down on the selector nob, while you also push in the little button and turn the nob all at the same time.
i have found, if you do any of these things wrong, then the beeping starts. but if you practice the process, it isnt really a tough thing to master.