Roll back noise?

Anyone else hear this? When I allowed my truck to roll back a little in drive it made a grinding / clicking noise. I did it again to see if would happen twice and it did. I don't intend on doing this again but was just wondering what it was.
2010 Dcab 4x4 trd OR 6cly auto (obviously)
Thanks in advance

 

how did you allow your truck to roll back in drive?

 

My driveway is steep including right at my house. I pulled too close to the garage door. I took my foot off the brake to roll back about a foot and heard the noise. My other vehicles don't do that. I was wondering if there was some safety feature on the Tacoma to prevent it from rolling back while in gear.

 

my 06 didn't make any noise but it did shut the engine down

 

Its not a good thing because you are putting the weight of the vehicle againsts a gear that is. Being driven forward. Grinding gears is what it is most likely. If you need to roll back a better choice would to be either put it in nuetral or reverse. As for stalling engine its like when you are driving a manual and you stall out the car due to not enough rpms to keep it in motion. I would defiantly avoid rolling back on forward motion gears as it can cause damage

 

I do have HAC but wasn't sure how it operated. I did not get a beep or light in the dash. It didn't roll back very far and it did feel like the brakes were still holding some. I won't do it again. Thank you.