I replaced the valve covers a couple weeks ago and i've got a strange sound coming from the engine bay when i start it up.
-The sound starts when i fire up the truck and last a minute or two, then aburptly goes away.
-It only happens when the truck is cold.
-If i blip the gas, the noise will go away for a split second.
-The sound is much louder in the cab. I can barely hear the noise if i try to listen under the hood.
-If i stand on the brakes let the clutch out (lower the RPM's to just above stalling) the sound will go away.

Can somebody please help me diagnose this sound. I can provide more info if it'll help. video of said sound below. You can hear the noise best at the end of the video.

http://s306.photobucket.com/albums/n...t=P6200086.mp4

 

Could be pilot bearing, or tranny bearings on the way out. Either way, I'd say it sounds like some type of bearing.

It might just be coincidence that you just had the valve covers off....

 

clutch/clutch out, doesn't make any difference. i agree though. it does sound like a bearing on its way out. I'm just puzzled as to why the noise stops after a minute or two.

 

Bearings don't always start then continue making noise...