2002 Envoy growl over 70mph

[dreinking]

I just started driving a 2002 Envoy and have noticed that I have a low growling noise all the time over 70 mph. Sounds like a drive train kind of sound...transmission or differentials. It worries me a bit as I am past 36,000 mile warranty by 2,000 miles. Turn your radio off and see if you notice the growl start as you accelerate from 60 to 75...trying to figure out if its unique to my vehicle or all Envoys do it. Thanks!

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I hate to be the one to tell you this, but that sound is definately not normal. Heres a few suggestions:

*Have you had your tires balance and rotated recently? It might be tire noise.

*Look in your glovebox. There is a sticker with "codes". If you have code G80, you need to change your rear axle fluid. Your locking rear axle may be binding. If this is the case, be sure to use only a high quality synthetic gear oil compatible with GM's requirements. VERY IMPORTANT.

*If you have 4 wheel drive, I would be checking the level of the transfer case. The only fluid you can add is GM's AutoTrak II available from the dealer. There are no substitutes.

*It may be your driveshaft U-joints. But at 3x,000 miles I cant believe this is the problem.

*BE SURE that if you do have 4 wheel drive, your switch is on "2HI". If its on 4wd or AWD, this will lock your front "hubs" and create noise.

My recommendation: Bring it in to a "free check" brake shop such as Midas or Speedy or such to start the "process of elimination". They will check the essentials (brakes, tires, driveshaft,etc etc) for free.
Buy a manual for your Envoy, they cost about $15. This will help you in maintenance tasks such as changing the axle oil or checking the Transfer case oil. This noise could be something as simple as tire noise or something as complicated as a malfunctioning transfer case/axle.
Good Luck!