Hey guys, just seeing if anyone has had this same issue before. My GS whistles or humms between 30 to 40 mph only when cold. After about 5 to 8 miles, the whistling goes away. It almost sounds like a turbine noise of some sort? Any ideas The car shifts OK and doesn't seem to have any mechanical issues, so I don't think it's serious. I just had the tranny flushed by a Lexus dealer if that helps any. Thanks!

Could be the brakes warming up. Or could be the wheel bearings warming up.

Is that known on these GS's? anything to worry about

Some models of tires are noisier than others and in cold weather this may be exaggerated. It may take 5 to 8 miles for tires (among other car parts) to warm up in cold weather. Once warmed up some tires are less noisy. Not sure if this is your case, but just wanted to throw it out there as a possibility. If this is a newer problem, have you changed tires since last winter?

EDIT: After re-reading your post I'm not sure its the tires although it sort of reminded me of my own situation. I have semi-noisy tires, especially noticeable when cold and they emit a different pitch at different speeds. What happens if you warm the car's engine up to normal operating temperature first in the driveway and then go for a drive. Do you have the same issue?

I will have to try that tomorrow and see what the result is. I noticed this happening right after the transmission flush and differential fluid change that I had done at the dealer recently. Prior to this service I had no noise issues. I hate bringing my car in for service sometimes I should probably call them back and alert them of this

you could try swirving your car around on an empty road to speed up the tire warming process like how Michael Schumacher does it
lol jk

could it be A/C compressor?

check your serpentine belt for glazing...

It's not the belt. I put it in neutral while I was driving and stepped on the accelerator, the whistling stayed with the mph not the rpm's. Also, the noise is there cold or warm, but more prominent when car is 1/2 warmed up. Tires don't seem to have anything to do with it. Bringing it to the dealership tomorrow, we'll see what they come up with!!

Same thing happend to me this morning. Would love an answer.

I've had the same thing happen to me. I've brought it to the dealership and they could not figure it out. When it was cold I would hear this high pitch sound, at around 30 mph, but, when it warmed up it went away.

I was reading this tread and thinking about the differential, then I read you had it serviced just before the noise started. Do you know what grade fluid they used? And is the noise coming from the back?

For the differential they used 80W90 Quaker State gear oil. I dropped it off today and explained the symptoms. They checked it out and said that it is the transmission pump in front making the noise, and they don't know why but everything seems to be in order. I'm wondering if the pump now makes noise becasue it has coarser FRESH transmission fluid in it? That's all I can think of. Anyway, I guess I have to live with it and see what happens.

Shouldn't you be using 75w90 gear oil in the diff? A lexus dealer should not really mess anything up, but make sure they used type IV tranny oil.

They did use type IV. I just thought it was odd that after the fluid changes, my car started to suffer from this noise. Maybe it'll go away after the fluid is in there for a while.