Harmony/humm coming from front end.

[Texsbluethunder]

Not a full size but part of my fleet

2000 GMC Jimmy, 122,000kms.

The front end makes alot of noise which isnt dependent on throttle. It gets into a harmony which changes with speed and is also felt in the floor boards and steering wheel. I have narrowed it down to the front end by unknowingly having different air pressures in both front tires (10psi difference) this changes the frequency of the harmony and when I evened out the pressures the harmany went back to "normal". I am assuming this is a differential issue due to the noise changing when the spider gears RPM changes.

Background story: We drove the vehicle for unknown KM's (less than 100) with it in 4wd on dry pavement, I accidently hit the switch and never noticed. Thsi was last September. I am thinking this was the start of the issue.

Anyone ever expereince this? I have a feeling a bearing is finally letting loose or a gear is worn.

I have checked:
Wheel bearings: 1 replaced other is tight
CV shafts: Nothing unusual
Stub Shafts: minimal movement at the diff.

any ideas?

Thanks, Alex

[NEUMANNZZ]

any fluid in the front diff?

[Texsbluethunder]

Yes, and I am trying 30% lucas in it to see if it changes the noise. I have changed the fluid and no large metal particles but is metalicy.

[mudbuddy]

If it looked like metal flake paint you have one or a couple of bearings on their way out.