Front end whirring sound when coasting around 1200 rpm

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Nov 8, 2018 | 02:30 PM
  #1  
Had my passenger front right side axle shaft inner and outer seals replaced along with wheel bearing and shims.

I have a 3" lift with transfer case drop.

After I picked up from the mechanic, now there is a noticeable WHIRRING SOUND COMING FROM THE FRONT END when I take my foot off the gas and coast around 1200 rpm.

Always there every time I coast. Whether in FullTime or Part Time 4x4 or 2 WD or Neutral.

Mechanic says that there may have been thicker gear oil previously which masked the sound and also contributed to blowing my wheel bearings/seals to begin with.
The mechanic also says that it needs a new Ring and Pinion, yet I had differentials serviced and inspected only 4 months ago.

Q: Any idea if this makes sense or know what the sound could be from before I spring for a new ring and pinion?

Appreciate any advice greatly!
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Nov 11, 2018 | 10:03 AM
  #2  
perhaps you can clarify at what speed(s) this noise occurs. trying to diagnose a potential drivetrain problem based on your description is impossible. 1200 rpm could be 5 mph or 75 mph. was any work done that required removal of the ring or pinion? if not, it’s highly unlikely whatever they did caused the noise.

a whirring noise from the dif points at a ring/pinion problem. in my experience it was a bad pinion bearing which allowed the pinion to move around.
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Nov 11, 2018 | 11:46 AM
  #3  
Quote:
perhaps you can clarify at what speed(s) this noise occurs. trying to diagnose a potential drivetrain problem based on your description is impossible. 1200 rpm could be 5 mph or 75 mph. was any work done that required removal of the ring or pinion? if not, it’s highly unlikely whatever they did caused the noise.

a whirring noise from the dif points at a ring/pinion problem. in my experience it was a bad pinion bearing which allowed the pinion to move around.
Thanks. Good points. Whirring happens beginning around 20 mph and continues up to 60+ mph anytime I take foot off gas and coast. The current work with the bearings did not involve any ring/pinion work just changing the gear oil after the outer seals and wheel bearings were changed.

Mechanic suggested maybe the other previous work had gear oil that was too thick that potentially blew out the seals to begin with.
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Nov 12, 2018 | 02:03 PM
  #4  
it’s possible that using a thinner oil than before will uncover some noise. it shouldn’t make any noise on deceleration (or acceleration). id check the rear dif for pinion wear and verify the wear pattern on the ring and pinion. problems like these only worsen with time.
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Nov 21, 2018 | 04:35 PM
  #5  
Quote:
it’s possible that using a thinner oil than before will uncover some noise. it shouldn’t make any noise on deceleration (or acceleration). id check the rear dif for pinion wear and verify the wear pattern on the ring and pinion. problems like these only worsen with time.
Turns out it was the oil, was a bit too thin. Regular weight 75W90 fixed the issue. May have called out a potential issue with the ring and pinion. I'll aim to replace in the coming months.

On the list!!!
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