Trilkb

You know...to me it sounds like its coming from the center of the rear. I'll look into that.

gebo

I apologize. I had borrowed one and have taken it back. I never checked the front wheel bearings.

I’m embarrassed to ask the guy to borrow his again because his body language told me I had kept it too long the first time

gebo

Well, I got my very own stethoscope and I checked the front bearings and they are quiet. I rechecked the rear bearings and I can hear noise but considering everything a lot of other things are turning I don't believe they are bad. I just hear a little noise.
My understanding is that with a stethoscope I would not have any problem hearing the problem.

Here is additional info that may help in your diagnosis. I noticed that when I first get in and drive it cold that I have to go about 1/2 mile or so before it gets loud at 40. I was extremely happy when I left the tire shop and I prematurely celebrated
until about 1/2 to 3/4 miles down the road. IF it is not the tires and this doesn't appear to be wind noise and if my wheel bearings are good (I'm gonna have that verified Tuesday) then it looks like that center carrier bearing option. I just finished
up jacking and checking the wheel bearings and it is 90 degrees and I'm gonna have to verify the bearings before I start taking off all that stuff covering the driveshaft.

Today I was able to verify I gotta drive a little ways until the whirring grinding noise gets to its maximum stable level.

Does this help?

LS430inDE.

Isn't the rear supposed to be filled with 75W-90, full synthetic?

LS430inDE.

Regarding my prior post of the rear diff being spec'ed to be filled with 75W-90 full synthetic, and you stated you have 75W-110 in there. Also you mention you thought the noise was gone until you drove (warmed up the oil) "about 1/2 to 3/4 miles down the road.." that sounds like the noise occurs when the gear oil is heating up. The 2nd number in the oil is the warm viscosity. Your Amsoil (snake-oil in my opinion) is the wrong warm viscosity. Might be a longshot, but I'd change to the right stuff then start your troubleshooting (if necessary).

gebo

This is what I have learned on bitog.com

the old 75w-90 specs were modified a few years ago. The 90 weight classification was split. Now, 75w-90 is the light side of the old 75w-90 and the new 75w-110 is on the heavier side of the old 75w-90 spec.

Molakule told me to use 75w-110

You make a good point. i believe I’ll go and swap out the 75w-110 to the thinner 75w-90. What have I got to lose? $25 more ain’t gonna kill me.

Trilkb

I just jacked mine up and ran 8t up to 40-50 and got nothing. Fyi, turn traction control off to do this. Loudest thing I got was the rubber axle boots squeaking on each other. I did find out my passenger rear brakes are shot, in drive with my foot on the brake the wheel was still turning.

All I can think of is that rear diff carrier bearing someone mentioned.

I hate dealerships and the only 2 Lexus dealerships around here aren't near me. They are the only ones I trust to diagnose this correctly but I still feel they wont be 100% sure.

Another thing to note is that I've always felt like my rear shocks are blown/sagging. With the car on Jack stands and the rear suspension drooping I'm wondering if the geometry changes and i get no noise because of that. But same thing, noise at around 35 to 40mph. When it's cold it's not as loud. Things been screaming lately since its 90 out.

I'm 70% about to buy the drive shaft center/carrier bearing.

gebo

Trilkb,

I just ordered some Schaeffers 75w-90 gear oil and will replace that in the rear differential. I don't think that will fix it but it's simple and worth a try.

That should be done by Thursday. After that experiment I guess I'll go and start taking all those shields off covering up the drive shaft to check out the center carrier bearing.
Are you gonna get the OEM for some other brand?

Trilkb

The exhaust clamp on my cat has a super rusty bolt head which will snap or round off. The other 2 clamps after the resonators look fine. Remove that section of pipes and the tunnel brace will get you to the heat shield, remove the heat shield gets you visible access to the drive shaft. Should be simple after that. I'd start wrenching today but I'm hurt. So once the driveshaft is off youd need a bearing puller it sounds like. You may get away with letting the mufflers hang and just remove the intermediate pipes/y pipe, but those may need to come off.

I think if you are going that far then I wouldn't even "check" it. I'd just continue and replace and call it preventative maintenance.

Tools I see needed so far are a white marking pen to mark exhaust pipes and driveshaft location. One of those exhaust hanger removal tools would help. Then a bearing puller to get the bearing off. Maybe reuse the old bearing in front of the new for reassembly.

Then you have the joy of doing it all with the car 10-12 inches off the ground.

I may get a quote lol.

gebo

Which brand hanger bearing are you getting?

Trilkb

No idea, haven't looked to see what OEM runs.

Timken hb1006 probably

gebo

Ok. Let’s stay in touch.

Trilkb

Shoot, I wont be getting around to it for awhile. It sounds possible it's the issue though when wheel bearings check out.

StanVanDam

Both of my rear wheel bearings started making a metallic grinding noise that only made noise at low speeds (2-30km/h). Above 50-70km/h, it was silent. I thought it might have been the parking brake, so I took off both rear rotors and calibrated both star wheels so that the parking brake pads were adjusted perfectly. I still heard the noise, so after that, I was confident the problem was both rear hub bearing assemblies. Installing new Koyo 3DACF044DCFG rear bearings (from https://www.amayama.com/en/part/koyo/3dacf044dcfg) completely eliminated the noise.

At least the factory-installed bearings are extremely consistent in their production quality - the rear right side started the noise first but the rear left followed very shortly after, within 500-2000km.

Another possibility is that the noise is AC-related - the AC system makes noise emanating from behind the steering wheel column and brake pedal area. See https://www.clublexus.com/forums/ls-...ith-video.html

LS430 rear diff hypoid API GL-5 oil specs by year:
Aug 2000: Above -18C/0F SAE 90, Below -18C/0F SAE 80W or 80W-90
Jan 2002: same as before
Jan 2003: same as before
Jan 2004: If no synthetic tag, same as before. If synthetic tag present, SAE 75W-90 or equivalent.

gebo

Where in your car did you hear the sound? Could you by sitting in the driver's seat know it was coming from the rear bearings?