Fustrating sound-under carriage

[SoCalRunner]

This sound is driving me crazy and i cant find the source- turning to you guys for help. When driving on the highway 50-70 mph, i hear a sound coming from the under the rear side of the car. it sounds like something hanging under the truck and flapping in the wind. i have pulled over countless times to see what it might be but i dont see anything hanging. I even told the dealership about it at my last service and they couldnt find anything. Has anyone ever experienced anything like this? i have never messed with anything under the truck, hitch plugin, spare, nothing. :barf:

thanks guys.

 

[rook]

Check the aluminum heat shields which are above the muffler and some other places on the exhaust system. Some corrosion takes place and the washers no longer hold the shield in place.

 

[roofless]

Have you replaced the break pads yourself? Might have lost part of the shim kit w/spring.

see this thread
http://www.toyota-4runner.org/4th-gen-t4rs/21058-floating-brake-pads-3.html