Load noise

These Fords are known for lifter noise if its coming from engine which is a sign that the timing chain needs replaced. Does it sound like it is coming from the top of engine. Does it make noise when idle or on the gas and when does it go away, Could be a piston, bent push rod or bent crank to piston rod or loose bearing caps ect so try to hear where it comes from and/or get it to a shop.

Its when I'm at a stop light. It sounds under the front of the truck. Its sounds as if something is lose and hitting something and it's loud. But when I put truck in park can't hear it.. I'm also having problems with my air bags in rear passenger side

Could it be the muffler?

may but sounds like its connected to having load from the engine to trans when in drive gear. Either a strain on the engine or in trans when in drive. Possibly a belt ternioner, idler pulley if sound is near front of engine. If sound is under truck, there are sensors in trans Input & output sensors may be bad. May lift hood to see if you can narrow down noise location. I am afraid you may need to get it looked at to fix, If its in the trans (sensors are inside it.) Most can be changed out with trans installed so not too bad but in some instances the valve body may need to come down which I do not suggest a novice doing so. If its an accessory on the engine like a belt tensioner its fairly easy, could be a exhaust leak, see if you can rev engine up in park to hear it, its possible.

The muffler is behind the rear half of truck, somewhere between the trans and rear axle so unless you hear the noise under the rear half of truck then I doubt it but could be a shield along the exhaust to the muffler or after it. May be best to get it up on a lift and have a shop locate it.

Yes the sound iscoming from under the truck in front area. And when truck is on and in park and I give it gas I can't hear it.. Only while it's in drive... Is all that you mention that it could be is it expensive?

And thank you so much for helping me I've had people look at it and they say muffler. But it's to loud and to close to front of truck to be that

My 2003 Expedition has the front cats going out. At idle they rattle quite loudly.

Get up on a rack. It could be cheap, the sensors in trans can add up but can be tested before buying. Like FOR has suggested front cats, just need to confirm. I think if it was a belt pulley it would be making noise all the time and likely exhaust manifold leak would too, So that tends to leave the trans.

But yet need to confirm, And I am not hearing it but having to go by a description, so it is a guess.

I will get it to a shop thank you enginecreator.. You were a great help.. F_O_D I I have stupid question what are cats? I know nothing bout that

Catalytic converters.