Rhythmic Scraping Rubbing Noise in Front End (AWD 06 Denali)

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Hello Forum:
I have a 06 Yukon Denali AWD 6.0 Litre. The last 10K miles I have been experiencing a rhythmic sound from the front end. Mostly I hear it at 30-40 Mph coasting to a stop (engine not under load) and also if I put it in neutral and coast along. It is like a light scraping or metalic rubbing. I cannot hear it under load at highway speeds or while accelerating mostly because of the overall noise level.
The truck has 140K on it.

Here's what I have done so far:
1)New rotors and pads. (+2007 Upgraded calipers)
2)New Wheel Bearings (Moog)
3)Front U joint.
4) Put silcone on CV Boots.
5) Jacked up on stands and turned front wheels in Neutral and cannot hear anything.
6) Rotated Tires (Michelin LTX Defender)

My mechanic says I am too sensitive and says he could not hear it. I am concerned it might be something in the Transfer Case or something that would leave me by the side of the road. My wife says to look at new trucks but they are priced out of my range nowadays.

I run it between Florida and Michigan (winters in Florida) so it mostly has highway miles ( I got it at 47k).

Any help or ideas would be appreciated.

 

[Doubeleive]

have you checked the front differential?

 

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Thanks. I had the fluid changed a year ago but it is worth looking at that again. Makes sense that it might be audible when coasting at 35-50mph.
M

 

[Sam Harris]

Hello Forum:
I have a 06 Yukon Denali AWD 6.0 Litre. The last 10K miles I have been experiencing a rhythmic sound from the front end. Mostly I hear it at 30-40 Mph coasting to a stop (engine not under load) and also if I put it in neutral and coast along. It is like a light scraping or metalic rubbing. I cannot hear it under load at highway speeds or while accelerating mostly because of the overall noise level.
The truck has 140K on it.

Here's what I have done so far:
1)New rotors and pads. (+2007 Upgraded calipers)
2)New Wheel Bearings (Moog)
3)Front U joint.
4) Put silcone on CV Boots.
5) Jacked up on stands and turned front wheels in Neutral and cannot hear anything.
6) Rotated Tires (Michelin LTX Defender)

My mechanic says I am too sensitive and says he could not hear it. I am concerned it might be something in the Transfer Case or something that would leave me by the side of the road. My wife says to look at new trucks but they are priced out of my range nowadays.

I run it between Florida and Michigan (winters in Florida) so it mostly has highway miles ( I got it at 47k).

Any help or ideas would be appreciated.

I’d be looking at the front diff too.. and for the mechanic’s words… not cool.. if you know your vehicle, it’s imperative to pay attention to any details like this. Noise, odor, differences in power, drivability, etc… good for you, knowing your rig.

 

[B-train]

Those were known for front diff noises. Especially at the mileage you are at. I would service it yourself if you feel comfortable and see what the fluid looks like (most likely a silver-ish brown color I would assume). The drain plug has a magnet that will probably have its winter coat on as well (fine particulate).

If not comfortable find a better mechanic that actually wants to do good work. I would speculate that a couple services in a shorter time span will clean it out. It won't fix scarred bearings, but will most likely lengthen its life. These differentials can run for an incredibly long time given the crappy condition of the fluid in most of them.

 

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Thanks. If I see problems in the front diff fluid - any idea what front diff work might cost? Perhaps Inner and Outer Bearings?
If it was being worked on would the prudent move be to replace the CV joints and 1/2 shafts as well? (Part cost on those seem manageable).

Many thanks for the insight and replies. I just put new leather coverings on the seat frames (now that's tedious work) and the whole rig looks pretty good. Better than new trucks on the used car lot these days so I'd like to keep it running well.
M

 

[Mudsport96]

If the front diff fluid is bad, i would probably look for one at a junkyard and rebuild it. That way the rig is only down for the time it takes to swap over the part.
Getting one with the correct gear ratio is the key but once that is done and the unit is rebuilt, you install it and have the original to rebuild and have on hand for the next time.
And i say next time since the awd diffs seem to have repeated issues vs the regular 4x4s. Guy in town has put 3 front differentials in his 05 in 160k miles.

 

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Wow. Good to know. Thanks. I'll report back on progress. Your input has convinced me it is not all in my head!
M