High pitched whine 2011 2nd gen 4x4 4.0

Hi I am new to the forum. I love my truck, recently purchased it in March with 83k on it. I have one issue with the truck. Every morning when I start it up, i back down my driveway, put the truck in drive and as soon as I touch the gas I get one quick EEEERWUH high pitched whine or screech and thats it. Im thinking it could be the driveshaft? i have had it happen in reverse as well. I do grease my U joints a fair amount. Any insight would be much appreciated. Hoping to figure this out and make necessary repairs myself. Thanks.

 

You say just in the morning... sure it’s not a belt slipping from condensation?

 

Welcome to TW. Can't really diagnose sounds over the internet. Try recording a video with sound (even then it's still iffy).

The ABS module does a self-test when you first exceed ~5 mph in either forward or reverse, but the sound isn't high-pitched.

The front brake pads have some play within the calipers and can make a metallic clank during a reverse-forward direction change, but again not high-pitched.

 

I guess it very well could be, but it sounds like it comes from the middle/rear end of the truck. It also did it during the summer, and every once in a while it will happen when I leave work at the end of the day. So it happens when the truck is cold or atleast not up to temp.

 

Middle/rear end of the truck? Check carrier bearing for excessive play. Could also be grease drying up in the driveshaft slip joint. Both components move with direction change because of axle wrap.

 

Thanks 3JOH22A, I can try and make a video, im convinced its a drivetrain sound. I plan to do some diagnosis today. I’ll post my findings.

 

Yes and I have checked my center bearing and I do have a fair amount of play there. Im from CT and my carrier bearing is pretty rusted with a good amount play, nothing extreme but I believe it should be tighter.

 

Untie the cat from the fan blade.

 

I’m pretty sure that is normal. I can’t remember what it is specifically but I think it’s the transfer case or ABS testing.

it only does is on cold starts and doesn’t happen again right?

 

Yeah thats correct usually once in the morning at 7:30 and once on the way home from work at like 5:30

 

Totally normal.