Gmt900 Driveline Noise

[biggin'89]

Im hearing a noise that seems to be coming from the rear of the driveline. I'd describe it as a whirling noise maybe even a rotational roar/growl. The truck is a 2008 gmc 1500, 5.3, 4wd, currently 68k miles, but has had the noise since it was bought with 57k miles. from gm that was certified. I've searched and really only find info on the nbs trucks that have front diff issues, but this is coming from the rear half of the drivetrain for sure. has anyone heard of anything like this? Im going to change the transfer case fluid since i don't know for sure if its been changed. i checked the rear diff fluid and it was full but dirty so i'll also change that. the transmission fluid is full and is very clean and smells as good as tranny fluid can (not burnt). I took a video that you can hear it in. It was taken with my cell so its not great. In the video im only going 15-20 and what you hear is not the tires. It also changes pitch when i let off the gas and even blipping the throttle slightly so it doesn't shift you can hear it change pitch between on the gas and off.

http://s146.photobucket.com/albums/r277/ky...t=VIDEO0012.mp4

 

 

 

sorry about quality just listen don't pay attention to video unless you were a fan of the blair witch project

[govtech]

you have warranty remaining you know,,not your problem

 

take it in and road test it with the shop foreman sitting to your right..to duplicate it

[biggin'89]

Ok, just got the truck back. They ended up replacing the pinion bearing and side carrier bearings.