metallic rattling noise in 2001 silverado

[swampboy]

My truck (2001 Silverado 4.3, 5-speed, 4x4) has developed a metallic sounding rattle upon accelaeration. It does not do it all the time, although it is beginning to get worse. It is coming from the passenger side rear. It sounds like a muffler or something similar like sheetmetal but I checked and did not find any loose mounts or anything else. I thought maybe wheel bearing or u-joint, but can not tell if there is something wrong with either of these. Plus it doesn't do it all the time which I figure it would if it were a bearing. Anyone know what this could be? I recently put 265 tires on and had the rear brakes done (pads, turned rotors). The sound drives me nuts when I take off and accelerate. Any help is appreciated. Thanks in advance.

[nathanmontez]

i have had the same problem in my 97 silverado for about a year and i still can't figure out where it is coming from

[swampboy]

I finally broke down and took it to the shop.....my first suspicion was correct--U-joint. THe rear u-joint wore out. Now why it would wear out with only 66000 on the truck is beyond me. THe mechanic said that b/c it was a short bed the extreme angle of the driveshaft predisposes the u-joint to wear. Makes sense........Now you think chevy would take that into consideration and perform a little engineering ingenuity, right?