My 2008 Grand Caravan (4.0l) has done the same thing since Dec 2011 @ 51k miles. I have had the starter replaced, the WIN module, keys (not for this problem) and have had it to the dealer for this same problem at least 7 times over the last 18 months and 33,000 miles. I've been through 4 batteries (batteries are NOT the problem) and have had it happen under almost every TOTALLY RANDOM circumstance. Something (electronic, I suspect) is blocking the starter from spinning. The sound it makes is that of the starter bendix kicking in but the starter doesn't spin. Hot, cold, dry, wet, engine cold, warm, daytime, dark, remote start, key start, & any other pattern or condition you can imagine has been tried. THIS IS A TOTALLY RANDOM behavior & of course the dealer says they cannot duplicate it. The one time they did get it to duplicate, they replaced the WIN module, but that didn't fix it. I've had it go as long as 3 months without a symptom & once had it do it eight times in a row in one day, only to take it to the dealer the next morning where they couldn't duplicate it, although they kept it a full week & did nothing. I have the top of the line full Chrysler warranty & they have refused to make an educated guess as to what may be the next part to try and replace. My service tech said it would either be the WIN module, keys or main computer for the van when I first took it in, but we seem to be at an impasse. I have a multiple videos of this behavior, including one of it taking 146 key turns before it started!! It's not the starter (replaced once, no change) it's not the keys (we have two & it does it with both), it's not the WIN module (replaced, no change), so figure this out Chrysler!!! My 1996 F-150 that I paid $300 buck for starts EVERY TIME I turn the key. My $40,000 Dodge Caravan gives me a crap shoot!!!