For those of us who 4 wheel year round I can guarantee that that grinding is of little consequence. As far back as I can remember (1970s) all transfer cases with the manual lever will grind some. While in park, start the Jeep, put it in neutral and grab the transfer case handle and shove it forward. Then with the brake pressed, put it in drive and reverse to make sure it is in gear. If you don't start the engine you may not get the T-case into 2wd as the gears may not be lined up. When it is running the gears turn slowly but will go in. The Jeep transfer case is built to withstand a lot more than you putting into 4 high and back to 2wd.
On a side not, when putting the t-case in neutral make dang sure that it actually out of gear by putting your Jeep in drive and reverse and then back to neutral. I have had a few times it wasn't in neutral. This would be bad if you towed it and it was in gear. Just make sure you turn the engine off while tranny is in neutral before you put it in park. Easy, right?
On a side, side note....my manual is still using pre-2012 instructions that say I need to leave the key in the ignition. Wranglers haven't had a locking wheel since 09.