When my truck is in park there is no noise. There is a clicking noise when truck is put in reverse or drive. It is coming from the front end underneath. Doesnt do it when truck is in park. Doesnt seem to get louder when accelerating just constant clicking noise.

 

It may be one of the front auto locking hub's going bad if it is four wheel drive. Is it four wheel drive??????

 

yes my truck is 4x4. also i have noticed if I am at a stop while in drive it doesnt make the noise but then if i go to turn the air on - it begins to click as well.

 

It seem's like it is coming from the front wheel's right? If so that is it. You will have to put manual locking hub's on it. Or pay $350.00 from ford for 1 new one.