Front end groan in time with wheel rotation

[z0lt3c]

Zolt, I took a ride this afternoon and switching the truck in and out of 2wd and 4wd while also turning left and right. No matter what I do the sound is the same. I stopped by the local mechanic and he thought it might be the front differentials. He's suggested changing the differential fluid and seeing if there is any junk in there. I'm pretty sure now it is not the wheel hubs and I think the differential fluid check might be my next course of action.

I'll report back I get that done.

I was also thinking differential too, but based on your feedback, it sounds unlikely the differential would be the cause, given you have the problem in 2WD and it does not change with speeds.

If it's not a brake component (stuck pad, bent dust sheild), or a wheel bearing, or an axle shaft, or a differential, or a tire... the only think really left is the transmission? Do you get the same sound in reverse? You may want to try rotating the tires just to see if anything changes.

 

[LiverpoolSox]

I tried in reverse in both 4wd and 2wd and the sound is not there. Not sure what that means

In regard to the differentials and the sound being in 2wd and 4wd would the front differentials be engaged but not powered in 2wd so hearing the sound in both makes sense? I am admittedly a bit out out my knowledge base so please tell me if I'm wrong.

To clarify, the sound is the same when I tested under different circumstances but that sound was not constant, rather, a periodic sound occurring in time with the revolution of the tires.

 

[z0lt3c]

If you haven't serviced your front differential, thats not a bad idea, regardless, although it's very hard to diagnose a differential definitively without actually opening it up. Whats your mileage?

I am more familiar w/ the AWD drivetrain, but usually a differential/bearing problem will change pitch/volume based on RPM and/or speed. It sounds like your noise is constant so it still sounds like a bad fit (unless the diff is empty).

Honestly if you are saying it goes away in reverse, you may also want to look into servicing your transmission. At least check the trans fluid levels and make sure it's full. Otherwise, issues w/ brake pads can also go away based on directional wear.

It maybe worth it to pay the dealer the diagnostic fee and get them to isolate the problem, a bit better, and then come back here for advice on the best solution.

 

[afpj]

I tried in reverse in both 4wd and 2wd and the sound is not there. Not sure what that means

In regard to the differentials and the sound being in 2wd and 4wd would the front differentials be engaged but not powered in 2wd so hearing the sound in both makes sense? I am admittedly a bit out out my knowledge base so please tell me if I'm wrong.

To clarify, the sound is the same when I tested under different circumstances but that sound was not constant, rather, a periodic sound occurring in time with the revolution of the tires.

The drive shaft to the front diff does turn when in 2wd even when the front wheels are not engaged. Do you notice a change in character of the noise if you coast but put the tranny in neutral?

 

[LiverpoolSox]

Just heard back from my mechanic. He says when he drained the diff fluid the color was graphite there was metal in the fluid. So the answer to the question is that the differentials are the issue as I feared. He says he can look for a good used one and do the job for 1,800 or 2,500 for a new one. With 146k on the truck I'm leaning toward the used.

Any thoughts on whether this price is reasonable?

Thanks for all for help.

 

[z0lt3c]

Its very common to find shavings in the fluid. The only way to diagnose the differential conclusively is to remove it and open up the case. That price is bonkers... you can find a rebuilt diff on ebay for around 800 and labor should be no more then 300 or so.

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[black79ta]

I have gone thru the same road..howl that increases with speed can describe it as a 1 speed transmission if that makes sense. I replaced the unit hubs also the fluids
in both diff ' s and T CASE. Still have the howl. Bought a chassis ear setup (remote mics) and have confirmed the noise is in the front diff. Am going to rebuild it myself. Never done it before but ...will learn...

 

[redemn93]

there are videos on youtube of how to remove and open up a front diff on these trucks. usually all you need is carrier bearings. might as well replace the axle seals while at it. the pinion bearing are usually still plenty good and usually the differential itself is fine is you catch it in time. no reason to mess with those unless you confirm they are bad while on the bench. im going to have to do this soon to mine. a kit with quality carrier bearings and seals can be had for way less than $100. remove the front diff is cake.

 

[04_yukon]

I had the same problem on my 04 Yukon it was my front diff :-(