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2003 Yukon hum / vibration

sagent

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sagent Enthusiast

sagent

Posted
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I posted on this subject a while back and would like to update situation and ask for further advice. I just took above truck on a 2000 mile road trip and when cruising on highway between 65-75 I get a slight vibration / low pitched hum in cab. It stops at 75 and then starts again about 78 Mph and up. I took truck to local Walmart as I am away from home to have all tires balanced. They said all tires were "chopped" (?) and had to be replaced stating balancing would do no good. The tires are nearly new Firestone Wilderness LE, all pressures are right on. Vibration / noise is at the worst at 70 MPH

 

Does this sound like a U-joint? I put transfer case in neutral and checked rear prop shaft but could not really feel any play. I know front propshaft joints are ok.

 

Any suggestions? Thanks

98 Z71 SLT Senior Enthusiast

98 Z71 SLT

Posted
Posted

I work at a GMC dealer. We have seen ALOT of front differential problems. That's what I would start with.

Get a drain pan, crawl under the truck, and take out the drain plug for the front axle. If you have lots of small metal fragments attached to the magnetic drain plug...you found your problem. GM had problems with the actual bearings in the front diffs-the bearings would actually lose their finish/become pitted and noisy. If this is your casy---you are looking at a complete rebuild of the front diff.

Remember to refill your diff. fluid before any driving.

 

It's real tough to say what your noise is...you could also have a front wheel bearing that is noisy. You could also have a rear pinion bearing that's noisy also. You could also have crappy tires??

 

I'm just giving you a place to start.

sagent Enthusiast

sagent

Posted
  • Author
Posted

I did change all fluids over to amsoil except antifreeze and did not notice any significant metal on front Diff drain plug more than what i would like to see but still not that bad. Its hard to explain but it seems to me the noise / vibration is coming from rear of truck as there does not seem to be any vibration through steering wheel, more in the seat of your pants. Thanks for advice

sagent Enthusiast

sagent

Posted
  • Author
Posted

Also forgot to mention this truck is fulltime 4WD with the NR4 borg warner transfer case . I don't know if this changes anything.

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