norcaltc - I too have the exact issue you described. Just started this morning on my 2012 GC SRT8. Loud clicking / ticking sound under the chassis, behind the engine. It happens as soon as I start it for a few seconds, then again when I move the shifter into any position. Like something is cycling. After a few seconds it goes away until you take your foot off the brake and start moving, then the ticking starts up again. But I cant tell how long it lasts when moving.It is not normal and my 2013 Grand Cherokee Overland with the HEMI just started doing this at 47K miles. It is driving me crazy! The noise is from under the chassis behind the engine. It does the rapid clicking for a few seconds then stops. It does it in park at startup, in drive, neutral and reverse but only for maybe 5-10 seconds.