truck is an 08 FX4, i am getting a noise i never heard in any other car. i am getting a shrieking noise when the truck is under a load. it does not matter how fast i am going or what gear i am in. its not a belt noise it sounds like a wind noise almost but from under the truck. i have the magnaflow siso exhaust that has had a slight exhaust leak at the y pipe since i installed it, but it has never made a noise and i have never heard this noise. anyone have any ideas? the weird thing is this noise started after my windshiled was replaced but the noise is not anywhere near the windshield. hope someone can figure out what i am talking about from the terrible description i gave.

 

sounds like a belt is loose to me....try checking the tension on your belts and see if they need tightening.

if it is under accelleration and load I would assume the window replacement is just coincidental timing and has nothing to do with your problem.

 

the truck is an 08 with only 30k on it, no way to tighten the belt, it uses a auto tensioner. plus it is not making a belt noise

 

the truck is still under warranty so i made an appointment for monday to have it checked and the tranny fluid changed while its there. i will let you guys know what it turns out to be. hope they can figure it out.

 

Subscribing. I am curious to hear what the stealership says about it. I suffered the same thing when I first put a CAI on the truck (and only when the engine was under load) and was told by a few on here that it was a detonation problem caused by the CAI. Put some custom tunes on the truck and started using 93 octane only, and all has been fine since then (3 years have passed), but noticed a couple of days ago that the noise has returned although it's not as pronounced or as frequent as it was in the past. Had started using gas from Royal Farms exclusively, which has that E 85 in it, and started to think that was the issue. I have since put some Texaco in it and haven't noticed it since. Will be waiting for further input. Thanx!!

 

well i got my truck back. good news is it was totally covered under warranty which is great. it turned out to be a broken vacume line to the front right hub, not sure where it was broken but it was causing the hub to semi engage causing the terrible noise. now that i think of it i got a slight shudder in my stearing wheel also. so if you have a screaching noise that seems like its a heat shield but has that air leak kinda sound also then this may be your problem.