I have a 2005 GMC Sierra Z71 4x4 that recently started making a loud creaking noise in the front end. It is very loud and occurs instantly when turning the steering left or right, and also is noticeable but much quieter when going over bumps at lower speeds. At high speeds I don't hear the noise occuring. I have tried to located the source of this noise but I can't pin it down. Any ideas?

SOURCE: The rear problem with a 1999 gmc sierra truck

do you know if you have a limited slip rear diff?
if you do your grease is worn out or if the fluid was replaced it need to have a friction modifier put in the diff (can be found at any auto part stores.)

if its not a limited slip diff you might have spider gears going bad. then you need to remove the cover on the diff and inspect your spider gears and these are the spider gears
and this is what a limited slip looks like
good luck
and dont forget to rate my answer
thanks
paul

Wade Cook

• 6 Answers
• Posted on Jan 27, 2009

SOURCE: 4X4 inop on 2003 GMC Sierra 2500HD

I have found that when you are going to engauge 4x4 high, it is best to only be going about 3 miles an hour. Not faster, not stopped. It likes some movement to help it mesh. I've had perfect shifts since I started this. Hope it helps. Wade.

SOURCE: 2001gmc sierra 1500HD have a loud humming noise

check your wheel bearing at high speed they will make little. jack up the truck grab the tire on the top and bottom and see if you can move it back and forth if so , good chance bearing is bad

SOURCE: where is the 4x4 encoder motor sensor located on my 03 sierra

the encoder motor sensor is inside the encoder motor. the encoder is located at the transfer case. Remove the encoder and by part number 88962315 this is the sensor. you will have to retime the motor after
hope this helps

SOURCE: Ned to change the oil in transfer case

The Z71 typically comes with the auto 4wd transfer case (cannot remember the GM number). This requires AutoTrak II, which is available at a GM dealer. Do not use any other fluid in this transfer case! The previous post was correct in the location of the two plugs, but not on the fluid (the other types of transfer cases by GM use ATF). The transfer case is located under the truck right under the cab. There is a small skid plate under it, and a large driveshaft leaves the rear end of the case heading to the rear differential (axle). If you have the manual or electronic w/o auto 4WD transfer case, you can use Dexron III, but Dexron VI is a better fluid that is also now available at your local auto parts store. Again, if you have the AUTO 4WD button in the dash, use the AutoTrak II fluid from the dealer.