Concerned about my transmission

[GasSavers_rGS]

Ok, so I drove to an errand site and this site doesn't have the FE-style 'H' parking spot in the parking lot but a non-FE-style 'U' parking spot with a curb at the closed end of the 'U'.

So I tried to coast my car into the 'U' shaped parking spot and ended up nudging up against the curb. Since I was at a complete stop, I popped my gear from D to P, then shut off the engine. When I was done with my errand, I hopped into my car, turned on the engine, and when I tried to shift the gear from P to D, there was a somewhat loud "thump" sound. I'm guessing "thump" sounds are not good when it comes to trannies.

So I guess my question is, for future reference, would it be better to change gears from D to N, then from N to P before shutting the engine off? That way, it may release some of the rotational tension that was created due to "nudging against the curb?"