At start up I have a rattle, sounds like from passenger side, lasts afew seconds, then goes away. Got under the truck and found the noise coming from the bell housing. Most of the rattle goes away within a few seconds but there is still a continous rattle from inside the bell, just not as noticeable unless I am under the truck. I heard of problems with starters and gears not retracting, could this be the problem? I do live in the country and the roads are very bumpy, could something have come loose?

 

sure its coming from the belhousing??. sometimes a loose heat shield can make all kinds of racket.

 

I'll put money on the catayltic converter inner shield rattling. Ford had a huge issue with it.
Alan

 

I had the serial/part number metal tag from my cat rust off and set on my inner heat shield, just removed it, all fixed! It made a TERRIBLE noise.

 

when i pull up to the drivethru at mcdonalds that shield rattling is annoying.i have 130k so... im on borrowed time with them anyway. no problem magnaflow high cats going on

 

Band clamps are supposed to work really well! lol

 

I put my ear up to the housing, and that seems to be where the noise is coming from, plus I checked the heat shields on the cats, they seemed secure.

 

I too had a serial number tag that was bent and rubbing on the frame. It made a terrible noise.