I did a search and found a thread on the 3rd Gen 2003-2007 page that seems just like what I'm experiencing with my 2008: After sitting overnight, within a few seconds of starting, whether in Park or in Drive, there is a momentary, maybe a second or so, grinding/engagement noise that last about a second. Never heard it unless truck has sat for overnight. I first heard it a couple months ago and it didn't happen every morning but now it's every morning. Anyone seen this?

Thanks

 

my 07.5 did the same thing but ot only did it in the warm weather,maybe has to do with the air conditioning being on it hasnt do it at all this winter.let me know if yours does with the a/c on.then turn it off for the next day.mine only did it with first start up of the day.

 

mine has done the same thing.But my truck sits for a few days at a time.Nothing seems to be broke an no fluid is leaking so I'll keep driving it.

 

It's the air conditioner clutch engaging. If you have the defroster on when you start the truck you should hear it as the ac is used to help get moisture off the widows out of the air in the truck. I have not heard mine for a while, maybe it gets better after some break in.

DJ

 

Mine has not done it in a while either. It is more of a grup than a grind and always when the AC was on. I always just figured it was the AC and nothing to worry about

Chris

 

I just don't see how it could be the AC clutch because it only happens after the truck sits overnight, and only on the first start of the day. I had my wife start the truck this morning while stood in front with the hood open. I was leaning on the radiator and really felt the vibration when the grinding happened. I'm wondering if it could be the fan clutch? I've got an appointment with the dealer tomorrow to drop off the truck near closing so they can let it sit overnight. There's an open recall on the truck so they'll take care of that too. Hope they figure it out.

 

kind of courious what it might be keep us posted.if you are doing the dash mount recall it takes about 30 min had mine done last week.

 

right on the money! it's the a/c. let your truck sit like normal, then start i with the a/c turned off. it won't make the noise. then switch the a/c on, and you'll hear the noise. funny my dodge has maybe done that once or twice (literally), but my '05 ford did it all the time.

 

When the AC clutch engages so does the fan clutch. It is normal.

Try this, have it sit over night and when you start make sure the AC/defrost is off, fan is off before you start. Once at idle turn the controls to defrost and then turn on the fan. I bet you hear the same chunk sound.

Don't waste your time at the dealer.

 

Mine has always made that clunk/grind noise. The service guys told me it was nothing to worry about. Sure makes you jump sometimes, sounds like a cat caught in the fan belts to me (been there once).

 

My dealership replaced my A/C compressor because of it. Hasn't made the sound since. Of course, I've made sure to turn my A/C off before shutting the truck down ever since also, so that may have helped.

 

Mine did this the first few months also on my 08. I would do it only about once a month so the dealer would never have been able to hear it.

It now only does it once in a while, but I only have 5k on it at one year old. It also did it once in a while when I would first turn on the AC.

So far no problems...

Chris