Rear End Howling Noise?

[skiguide13]

I'm experiencing a howl from what sounds like the rear end.

This only happens when above 40 mph and while maintaining speed or accelerating.

Does not do it while coasting, regardless of speed.

I've replaced both inner and outer wheel bearings, didn't fix it, replaced pinion and carrier bearings, andits am still doing it.

What else could it be?

The gear set had worn, but nothing significant, in pretty specific pinion pre-load, and backlash is in spec as I used the service manual to set it all.

The backlash was .007, and the pinion pre-load was 35 lbs.

The pattern looked good as well.

When shimming the pinion, I just reused the shim on the pinion.

So the pinion depth remained unchanged.

The truck is 07 6.7L Cummins 220k miles 11.5 rear end.

Thoughts?

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[AK Bob]

When you hear a whining or howling noise, it is usually caused by a damaged or worn-out ring and pinion gears.

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[skiguide13]

When you hear a whining or howling noise, it is usually caused by a damaged or worn-out ring and pinion gears.

Thats what I thought would be my next step.

Any way to identify what ratio gears are in there currently?

I was looking at the ring gear w and could see any identifying info.

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[AK Bob]

Thats what I thought would be my next step.

Any way to identify what ratio gears are in there currently?

I was looking at the ring gear w and could see any identifying info.

If you know the gears are original to the truck, you can use the VIN to check the build sheet.

Otherwise, you could jack up the rear wheels, mark the driveshaft, rotate the rear wheels forward one complete turn, and watch the number of turns and partially turns the drive shaft rotated.

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[skiguide13]

If you know the gears are original to the truck, you can use the VIN to check the build sheet.

Otherwise, you could jack up the rear wheels, mark the driveshaft, rotate the rear wheels forward one complete turn, and watch the number of turns and partially turns the drive shaft rotated.

I know someone has been in this rear end before.

I'm not sure if they are factory.

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[AK Bob]

I know someone has been in this rear end before. Im not sure if they are factory

Then I would go with the above procedure unless you can count the ring and pinion teeth to divide.

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