Whine from front during acceleration/deceleration

[GXO]

It was a replace under warranty TSB specifically. The whine... Did you look at the diff supports?

 

[Perveance]

Crawled under there today morning, everything looks good and all bolts are very tight. No leaks or anything looking abnormal. Car was always in California, so almost no rust. Also no leaks from transfer case or tranny. Btw, in case I forgot to mention the tranny shifts very smoothly.

 

[GXO]

So you are narrowing it down to wheel bearings, CVs, or front diff. Have you drained and filled the front and looked for metal on the plug?

 

[Perveance]

Yes, I replaced fluids in the diffs and tcase, it looked pretty dark, as prev owner never serviced them, but not too bad and no metal for sure. A year ago I replaced diffs fluid in my trailblazer, and that one was way darker, but was driving perfectly, so it doesn't look like there is abnormal significant wear in the diffs, but I didn't look in there with the scope.

Also, after servicing the diff and tcase I haven't noticed any whine tone/pitch change. Also, whine is more audible when it's cold outside. No clue how to proceed.

Wheel bearings were checked, seems fine, and the whine's tone doesn't change if I change direction by turning steering wheel left or right, so it doesn't look like the wheel bearings. And the whine's tone is too high for the wheel bearings IMO. Don't know how to check CVs, but the boots are not torn.

 

[GXO]

Hmm. Sounds like you have either t case or diff gear issues. Would it be possible to record it?

 

[Perveance]

Maybe the chain in the tcase is stretched? Just to remind, when front drive shaft was disconnected, there was no whine. I'm not sure if there are 2 chains, one for front output and one for the rear output in the tcase.

Yeah, I'll try to record it, will post once it's done, the whine is pretty quite, but I've driven another 2007 gx with more miles but definitely no whine.

 

[Perveance]

Here is a link to the recording. I used a mic and my gopro, sound is not very good, but the whine is audible. Today it was wormer than last couple of weeks, and it sounds more like whistle.

 

[GXO]

That sounds like R&P whine to me. I have it because I went to 4.56s and lockers. I wouldn't be too concerned.

 

[Perveance]

Sorry, what is R&P?

 

[Arailt]

Ring and pinion.

From ringpinion.com

Several situations can create ring-and-pinion noise. If the gears have been quiet and begin to howl, they are probably worn or wearing. If the gears howl during deceleration only, it's possible that the pinion-bearing preload has loosened. Howling under acceleration at all speeds indicates that something in the differential -- gears, pinion or carrier bearings -- has worn or no longer keeps the gear alignment correct. If the gears howl while accelerating over a certain speed range, but not all speeds, it's likely that the gears are worn due to lubrication failure or overloading. When a newly installed gear set howls, suspect the design or setup.

 

[Perveance]

Thanks Dan and Arailt. I think you are right, this explanation and and cause sounds right to me. The whine is pretty annoying and it's more loud in reality than on the video. I have completely stock vehicle with Michelin highway tires. I never towed with it, but the previous owner might have used it for towing.

So I guess there's no fix for this, is that right?

 

[Arailt]

Seems like new OEM gears would be the only fix.

At lunch, I rolled down my windows as I drove through the parking garage at work. I noticed a very faint version of the sound you're experiencing. I'm currently under a Lexus pre-owned bumper to bumper warranty, so I'll bring it up next time I'm in for service. I'll let you know what they say.

 

[GXO]

Yeah, it is common in wearing gears...as they get older as well, or if they are aftermarket and still bedding. If they are worn they can eventually fail. If you lift or change the angles of the pinion it can also introduce a howl as they points of load shift as the pinion angle shifts with a lift.

 

[Perveance]

That sucks. When you guys say gear, do you mean the differential or tranny and tcase?

Btw, this truck has no lift, stock tires, all driveline original, only 110K miles.

 

[GXO]

diff

 

[Perveance]

Hmm, does anybody have an idea how much would it cost to replace the gears to a new OEM ones?

 

[Perveance]

Went to Lexus dealer for a service on a safety recall this morning and left the vehicle there, also asked them to diagnose the noise. Let's see what will they recommend. Will update the thread.

 

[Kidscollegefund]

Wheel bearing. I had similar sound just recently.

 

[Arailt]

I think he's already determined it's not a wheel bearing since the noise disappears when the front drive shaft is disconnected.

Also, I recently had a bad driver's side bearing replaced. It was a loud, droning grinding sound, not a whine like the OP's noise.

 

[Perveance]

Just got the GX back from the dealer. They said the noise was diagnosed by 2 different technicians and it's most probably from tcase or transmission. They said that they also test-drove another '06 Lexus GX for a comparison and said that the other GX also produced similar whining noise, so they concluded it's normal due to wear either in tcase or transmission.

So I guess 2006 was a bad year.