Perveance

Hi all,

I'm observing abnormal drivetrain whine or howl on my '06 GX470 which has about 110K miles. The noise is observed during acceleration at about 25-55mph when RPMs are about 2-3K. Can't hear the whine at higher speed because of road noise. Went to a couple of mechanics - all said it's normal. Test drove another '07 GX with 140K miles and that one didn't have any whine, so I don't think it's normal.
I've recorded it:
Been troubleshooting it for a while already. Wheel bearings are good. Checked and replaced all belts, installed new tires. Replaced transfer case and diffs fluids it was dark but no metal in there, no leaks, all nice and clean. One thing I found is that the whine disappears when the front drive shaft is disconnected and the truck is driven only with rear drive shaft. Rebuilt driveshafts but it didn't affect the whine at all

Has anyone here had/have anything like this? Any hints what it can be?
Thanks.

techrep

Have you checked the CV shafts ?

IanB2

Noise seems to be only there while accelerating, not while coasting? I'm guessing you can't replicate it by just revving the engine above 2K rpm without accelerating the vehicle? Is it louder in the car than what the video depicts? In the video it's pretty subtle, probably wouldn't even notice it if you had the radio on at a low level.

sheikhmax

Since you have checked everything else.... Try checking the ALT as it makes weird and loud whining noises before its on it way out. Or if it has a bad bearing.

Hope it helps.

gwebster

I have a 2008 GX with about 105k miles and it started to have a nearly identical whine. While I am not sure if it is related, I recently had the alternator replaced prior to the whine noise starting and I am concerned that the bearing in the new alternator could be bad as a previous member mentioned.

Perveance

The CV boots are dry and clean, no tears. Also, whine doesn't change if I slightly move steering wheel left or right, so I don't think it's CV shafts.

In fact the alternator was changed a couple of years ago. Gwebster, do you have the whine when car is in P and you just rev it up to 2 or 3K RPMs?

If I shift Transfer case (4wd) lever to N while driving the whine disappears right away. So I'm pretty sure it's not the alternator. Gwebster, does you whine disappears if you shift 4WD lever to N? (Not transmission lever, but 4wd lever, the one that has 3 positions: L, N, H).

Perveance

Exactly! Only while accelerating and not while coasting. Can't replicate it in Park.


It's a little bit louder when the car is cold. It is pretty subtle, but it's still bugging me and I'd like to find a way to fix it. Or hear from fellow GX owners whether your vehicles have the same whine or not.
Thanks!

gwebster

There is no whine from my GX when in park and at increased RPMs. Not sure about your other question -I did not want to shift the 4x4 selector while moving.

ALAN553

whoa...ya can't be moving transfer case lever while moving...car has to be stopped and transmission in Neutral.

Perveance

Obviously you can't shift from H to L while in D or while moving, but you CAN go from H to N if transmission is in neutral even while moving. After that in order to go back to H you would have to stop. I at least that's what I did as I didn't want to try shifting transfer case in gear while moving.

Also, I already tried driving without the front drive shaft. Please don't say I couldn't do that, with CDL engaged you can, but only for short period of time (1 mile) of course in troubleshooting purposes. It also completely eliminated the whine.

IanB2

You could drive with no front DS, CDL locked indefinitely if you wanted to.

Sounds like you may be dealing with some gear whine from the transfer case. I'd make sure you've got enough oil in there as a starting point, level should be checked with the truck flat, so if you need to lift it to get under, you need to lift the whole thing evenly and then fill till it comes out the fill hole.

Perveance

Thanks for your reply IanB2. Transfer case oil was replaced with Mobil-1 synthetic 75w-90 LS a couple of months back. No metal in the old oil. Now level is for sure correct. There was no change in the whine with the new oil at all!

Any ideas?

IanB2

What's it sound like in low range? I'd fully expect there to be some gear whine in low range, but have you tried it? You'd want to find some dirt/gravel for that.

Perveance

Yeah, in low range it sounds like 20x times louder and slightly resembles the sound I hear in high range. Don't know whether it's normal or not. Whoever reads this thread please comment whether your GX sounds the same in low/high or different. Thanks.
Here's how mine sounds in low gear:

sheikhmax

Do you always drive like that fast when in 4LO??