what is this rattling

[edadmartin]

Hello I have an 06 expy 4x4 no air suspension.46000 miles the serpenteen belt was changed out at 40000 miles. Ive developed a rattling from underneath, sounds like a bunch of nuts and bolts being tossed in a can. It happens intermittently and 35 or 80 miles per hour, It seems to be happening more often .I cant get a good listen to really verify where it is coming from.Seems toward the left side. Motor runs strong there is no steering or foot vibrations while running.Curious thing is when I put it in 4x4 high the noise stopped for over 15 minutes ,within 3 minutes after I took it out of 4x4 I heard the rattle again. I thought wheel bearings but the hub and discs were not to hot and no burn smell at all. I'm stumped, what do you guys think?

 

[edadmartin]

rattle on 06 expy

More info. We just got back from a ride trying to isolate this noise. After it came up to operating temp we started hearing it under load, going up hills here in Colorado springs. We sort of came to the idea that it has to do with the 2wd Awd linkage some how. When ever I go from 2 wheel to awd, the noise stops. As soon as I go back to 2wd the rattle restarts. Possible springs or plastic gears I don't know for sure,seems like something not being held in place,sort of half in half out of position. Any one have any thoughts?

 

[ELVATO]

Maybe jack up to front in 2WD, and try to spin the wheels by hand to better isolate the noise?

 

[edadmartin]

rattling noise

Well it turns out it was a cracked integrated wheel end solenoid.I never knew there was one!! It took my mechanic about 20 minutes to ID the thing, he also replaced 2 vacuum lines that were cracked and leaking. 195.00 and the ratcheting noise is gone. problem solved. There is a Ford tsb out on this part.2003-2006.

http://expeditionforum.com/showthread.php?t=4956