2006 4L V6 whine noise from engine

[Tripdaddy]

I noticed a high pitched whine coming from my wife's 06 Explorer. I was thinking it was a pulley or something to that effect. It is there when the car is not moving and even when it is. However, I pulled off the drive belt and it still makes that noise so that ruled out the pulleys and devices run by the belt. It is really prevalent when the engine is cold and quiets down as it gets warm. When warm, I can get it to make the noise around 2000 to 2500 RPM in park.

I may have to take a long trip soon and don't need a engine problem in the middle of nowhere.

Vehicle
2006 Explorer Limited 4.0L 134K miles

Any ides?
thanks

 

[Logangray02sport]

Timing chain tensioner may be at fault I have seen a lot of these making this noise at the dealership I work at. Customers usually decline repairing and I haven't seen any come back yet so I would recommend repairing but wouldn't be afraid to drive it

 

[Tripdaddy]

Since the tensioner in this case looks more like a slide than a pulley, what would be causing the noise? It there supposed to be lubricant in there?
If this is indeed the issue and there are no moving pulleys, it would seem to be more of an annoyance.
Do you know of a ball park number they charge to fix that? I have a feeling a whole bunch?

 

[Tech By Trade]

search harmonic balancer squeal.

 

[Tripdaddy]

Thanks guys. Tech, I'll look into that but I don't know if that is the case for the 2006 and newer models. The noise is more of a constant whine than a squeak-squeak.

 

[Tripdaddy]

Update:
With no visible signs of anything wrong and a impending family issue, I decided to take it to the dealership.
Of course, the whine was not there and they could not recreated it. I told them to keep it over night and maybe in the morning you will hear it. Yes, they did hear it in the morning and said it was coming from the tranny. They will have to open it up to look and do a transmission scheduled maintenance while they are at it. it was 70K mile since the last one so I said no problem, do it.
The fluid was on the low side but OK and the fluid was discolored. However no metal or other issues seem present. Had them keep it another night to see.

Updated 03/16/2015
it's been 10 days and drove it from Atlanta GA to Green Bay WI and back (about 2000 miles) and the noise has not returned.

 

[Lunchbox111]

I may have missed it when reading everything. Did you find out why the transmission was whining? I have an ‘06 V6 2wd. Mine does the same thing. Can’t hear the whining from in front of the vehicle, however, from under the vehicle it sounds like it’s coming from the tranny. Is much worse on cold mornings than on warm ones. Can hear it while idling, but gets worse when accelerating. Transmission feels like it’s shifting fine