Strange noise in 4WD

northcreek

Original poster
Member
Jan 15, 2012
3,338
WNY
Hi folks,I thought I might pick some brains before I dive into it.My New to me 07 Denali emits a high pitched whine when in 4WD.It's not super loud and you might not notice it in a truck but,the Denali is so quiet on the road that it's perceivable.
It's a sound similar to driving over rain grooves or tracked vehicle marks in the road.
I'm thinking CV joint as a starting point.BTW this vehicle only has 50K on it and was a one owner older lady's daily driver..possibly never in 4WD in it's life.
My hope is that someone can point me to a common problem and save me some work.I have a full set of dealer shop manuals....thanks in advance,Mike.
 

barron03

Member
Nov 20, 2011
960
Have you checked the fluid level's in the front diff and transfer case ?
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
I'd think fluids first as well. If she never touched 4WD she might think she can defer all maintenance of the system. Since some parts are spinning all the time even in 2WD, such as the CV shafts, troubleshooting noises can be frustrating. But more parts in the front diff and transfer case are moving in 4WD mode, so those two are the biggest suspects. Any difference between A4WD and 4HI modes in terms of noise?
 

northcreek

Original poster
Member
Jan 15, 2012
3,338
WNY
Thanks guys,To be more specific,I was thinking the cv joint on the front driveshaft since I don't believe that it spins in 2wd.I'm going to check the fluids tomorrow since it's still dripping from a romp in the snow today...Mike.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Both CV shafts (passenger and driver's side) rotate in 2WD mode. The front driveshaft (from the transfer case to the front differential) does not rotate in 2WD mode, but its articulation is a U-joint, not a CV. Just a terminology issue.
 

northcreek

Original poster
Member
Jan 15, 2012
3,338
WNY
Yeah, the engineers love to use/change terminology to mess with our minds,the manual calls it a constant velocity u-joint when referring to lubricating the drive shaft which BTW, used to be called a torque tube....go figure...Mike.
 

northcreek

Original poster
Member
Jan 15, 2012
3,338
WNY
>Well I ran it on jack stands with wheels on/wheels off and could detect no noise.
>Checked fluid levels and drain plugs for filings in front diff and transfer case.
>Replaced T case fluid.
>Driveshaft (front) u-joint is fine.
>rotated tires.
And the faint noise is still there,the service manual says that some gear noise is to be expected and in talking to a mechanic he says the same.
Maybe this truck is just too quiet when compared to my previous 4x4s.
I'll keep snooping and let you know if I find anything.I was hoping that another Denali owner might say "yeah mine does that too" and make me feel better but, that hasn't happened so far...thanks for the replys,Mike
 

Voymom

Member
Feb 3, 2012
2,523
northcreek said:
>Well I ran it on jack stands with wheels on/wheels off and could detect no noise.
>Checked fluid levels and drain plugs for filings in front diff and transfer case.
>Replaced T case fluid.
>Driveshaft (front) u-joint is fine.
>rotated tires.
And the faint noise is still there,the service manual says that some gear noise is to be expected and in talking to a mechanic he says the same.
Maybe this truck is just too quiet when compared to my previous 4x4s.
I'll keep snooping and let you know if I find anything.I was hoping that another Denali owner might say "yeah mine does that too" and make me feel better but, that hasn't happened so far...thanks for the replys,Mike


Does this whine/noise happen only when taking a tight turn? And does it happen more on one side(when turning) than the other side? I'm just asking because I had a Buick Rendezvous that had the versatrak auto 4x4, in other words it was 4x4 but I didn't have a choice on when to kick it in, it did it on it's own. I could always tell when it kicked in, and upon turning with the 4x4 on my rear end whined really bad, like a constipated cow (sorry) I have no other way of describing it.

We took it to a mom and pop mechanic and was told we needed a new rear end(costs 2k). I looked on TV(different site) and seen about the rear diff fluid and how it should see regular maintenance. Well the gear oil I needed was $65 a quart and I needed 5 :eek: But found a cheaper route....changing the fluid and not getting a new rear end lol. However after the fluid which was zilch had been taken care of in both the T-case and rear diff, the noise was still there. I fixed it by selling the POS and getting an Envoy:cool: I have not had ANY noises from any of my 4x4 gears (A4x4 4hi 4lo), I do hear a little bit of noise in 4hi and 4lo when turning as in 4x4 your turning radius is greatly decreased, but it is NOTHING compared to the Lemon I just sold. I can't tell you honestly what the noise was from, it could have been just normal whining from a grumpy 4x4 being made to turn a radius that was just to tight, or maybe it needed a new rear end, either way that thing was a huge waste. It had more problems in the rear end than Kim Kardashian, I couldn't take it anymore.

But just know that there will be some noise when turning having the 4x4 engaged, and you may hear more as it is a quiet running vehicle. If all else fails...well then, good luck! :biggrin:
 

Sparky

Member
Dec 4, 2011
12,927
The powertrain on yours and on the Trailblazers is the same, so I'll try to listen to mine next time I throw it in 4x4 mode (but with the way the winter is going I may not need it anytime soon). Thing is, if it is faint and normally there I might not hear it over the other little sounds my TB makes.
 

northcreek

Original poster
Member
Jan 15, 2012
3,338
WNY
Voymom, this noise is non-directional but,does require the burden of the truck to manifest itself,I could not duplicate the noise while on jack stands.I too swayed from GM products for a while prefering Nissan vehicles but, they break too and when they do it's alot more $$$ than the GM's.
My last vehicle was my first and last try at a Ford product..that POS Merc Mariner ate a transaxle annually...going from that to the Denali was like going from a catapult to the space shuttle,I think GM has me back.
Luckily I dont' have any of the Kardashian problems that you described but, that funny line did take my mind off of the noise for a while...Mike.
 

Voymom

Member
Feb 3, 2012
2,523
northcreek said:
Voymom, this noise is non-directional but,does require the burden of the truck to manifest itself,I could not duplicate the noise while on jack stands.I too swayed from GM products for a while prefering Nissan vehicles but, they break too and when they do it's alot more $$$ than the GM's.
My last vehicle was my first and last try at a Ford product..that POS Merc Mariner ate a transaxle annually...going from that to the Denali was like going from a catapult to the space shuttle,I think GM has me back.
Luckily I dont' have any of the Kardashian problems that you described but, that funny line did take my mind off of the noise for a while...Mike.

The Envoy is my second GM/American made vehicle that I have ever owned, other than that I was pro foreign :smile: And yes they break too and are sometimes way more expensive and harder to fix. I have had Toyota's, Mazda's, and Subaru's. So far though I am madly in love with my Envoy, he is just ripped from engine to tailpipe with hot sexy I6 power carrying the 275hp :redface: I have never had a vehicle so sexy in my life lol

Now, on with the real topic. My Lemon Buick needed itself to replicate the rear end noises. It was slightly biased on sides to manifest the noise, as in it was a much louder groan when turning tight to the left, but more of a whine when turning a hard right, before I got rid of the thing it started whining every time we turned. I was told several times that it was a completely normal sound for the vehicle, but thinking about where and who I bought it from, I seriously doubted it. The mechanic took his stethescope to the rear diff and listened and said one of the rear diff bearings had seized up and was making the noise, and needed a completely new rear end. However....I could have just allowed the rear end to take a crap and just driven it in 2wd, but I was really excited to have something I could play with in snow...which the Buick handled like pure crap, even with the versatrak.

Now you said the groan/whine is only in 4wd? Have you driven it a lot without the 4wd? I'm wondering if it's just common 4x4 noise? It is possible.
 

northcreek

Original poster
Member
Jan 15, 2012
3,338
WNY
Because I've only had this "rocket sled" about a month it has been in 2wd most of the time.Living here just south of Buffalo NY we usually put it in 4wd the day after 4th of July and leave there 'till the day before the fourth.This winter has been incredibly mild...they had to cancel the annual LaBatts pond hockey tourny because the Buffalo harbor is unfrozen.
And yes the noise could be normal drivetrain harmonics,I swear this truck is so quiet I have to look at the tach to make sure that the 5.3 is running.
Now having the Envoy I can't believe how many of these and TB's are onthe road,I'm wondering if Gm regrets driving a stake into the heart of these Gems....Mike.
 

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