I couldn't fin anything about this in the old posts, but this is the 2nd time I have had this problem with my '05 FX4. It is cold here, about 25deg F. I let the truck warm up this morrning for about 15 min. When I get onto the street, the truck makes a loud gear noise, almost like high speed in reverse. Its very loud, probably can hear it inside the houses on the street. If I switch to 4x4 HI, it goes away, even when going back to 2wd. Then adter driving a few miles, it returns, very load again. The truck has to be moving, If I slow down, the noise goes down. Anyone have this issue on cold days?

 

My 03 Sport Trac did this, after a few trips to the dealer they put on "chasis ears" and figured out it was the transfer case that was shot. It was replaced under warranty. Same as you, it would quit when I popped it into 4x4, and then it would start again when it was out.

 

My truck had a similar if not the same problem. But it did not matter if it was cold or not. It turned out to be the front hubs trying to engage. The dealer repaced a sensor and it has not done it since.

 

Only when cold? It was about 8 degrees here this morning, and the same thing, only a lot longer. If its above 25, there is never an issue?

 

Does this have something to do with the Integrated Wheel Ends? Could the cold air change the vacuum causing the hubs to engage just enough to tick?

 

I believe I might be having the same problem with my '04 Screw. Ever since it started getting cold out, I will get a rotational grinding noise upon deceleration. As I slow down further, and am almost at a complete stop, I will get a loud "clunk", which sounds like a gear engaging, and then it is fine. This first happened about 2 months ago, and at first would only do it when I first got in it, like in the morning on the way to work, or at night on the way home from work. Once it was warmed up after a couple of miles, no problems. I took it into the dealer on 11/15, they had it almost two weeks. The Service Manager told me there is a new TSB coming out, and that he would provide me with all of the info. regarding the TSB. He was very vague, but mentioned that it involved replacing the rear end entirely, with an "old style" rear end. He then said that he replaced some fluid somewhere, but was again very vague. He also told me that he considered this a band aid, and as soon as there is more info. he would let me know. I picked up my truck after hours, and lo and behold, no TSB info. and no notation on the work order about replacing fluid in the rear end. My truck worked fine (except for the vibration that i have learned to live with), until today. Now, this problem is worse than before, is happening more frequently, the grinding noise is louder and more pronounced. It sounds like the tranny or transfer case is trying to explode. Today is the first time this has happened after actually driving it more than a couple of miles. I am calling the dealer again tomorrow, and schedule another appointment. Luckily, my dealerr treats me well by picking up my truck and dropping off a loaner for me to use.