ashawn6841

Hello,

Hoping someone can help me diagnose this noise.

I have a 2008 IS250 Awd with 108,000 miles on it. I recently started hearing a noise mostly between 60-64mph I can hear it faintly at other speeds but very clearly in the 60-64 range. The noise is almost a "whirring" but disappears completely when I let my foot off the gas. I took it to the dealer who diagnosed it to a bad wheel bearing and changed the drive side wheel hub. The noise did not change at all. I had my doubts about the wheel bearing theory anyways since it disappears completely when letting my foot off the gas. I will be going back to the dealer next week for further diagnosis but wanted to see if anyone had any insight about it before I go back.

Also for background the dealer did recently change the differential fluid, trans fluid, and did the carbon build up csp.


Any insight is appreciated.

Thank You!

Gville350

iTrader: (10)

My thinking is perhaps it might be a half shaft since it only makes the odd noise during load. Do you get the noise at ANY other speeds while turning? Are you running stock suspension?

You don't have a 6-sp trans do you? Did the AWDs even come in standard trans?

ELITech

You could only get a manual in the 2wd is250...

My question is do you hear the noise more in the front or the rear of the vehicle?

If in the front... and it seems to disappear when you let off the gas, it's possible to have the front diff causing the noise... The car can be raised up on a lift and run in place to help diagnose...

ashawn6841

Hey guys thanks for the responses so far. To answer some of the questions, I do not hear any weird noises when turning in particular. The noise is not affected by turning either so if I'm going 60 around a curve the noise doesn't change at all it remains pretty much constant and seems to be related to that specific vehicle speed rather than engine speed. Also the suspension and everything on the vehicle is stock. It is a 6 speed automatic.

I have not really been able to tell where the noise is coming from next step will probably be to get it on a lift and see if it's something the tech can replicate while it's in the air.

If anyone has any other ideas feel free to chime in. I'll keep this thread updated as soon as I find a resolution as well.

ashawn6841

Just wanted to post an update: Took the car back to the dealer Tuesday and went on a ride along with the tech who worked on my car. He insisted he didn't hear anything even though I could hear it the entire time. He suggested I wait for the noise to get worst because he has no way to diagnose it. I explained to him that I only have 1,000 miles left on my extended warranty and didn't really have time for it to "get worst".

When we got back to the dealership I explained the same thing to my service advisor who went on a ride along with me and heard the noise herself. She is going to get with the shop foreman tomorrow to get this resolved since the first technician is apparently deaf.

I'll keep you guys posted. If anyone has any suggestions please chime in. I hope they don't just tell me to "let it get worst"

NYKnick101

I have the same thing i think your talking about. I went over the entire front end suspension and parts and I couldnt for the life figure out what it was. I think it was my tires because sometires have weird road noise. What kind of tires do you have?

ashawn6841

I have the continental extreme contact dws tires. I do not think it's the tires though because the second I lift off the gas the noise disappears.

ashawn6841

Just wanted to post another update and ask for anyone's advice. Picked up the car from the dealer. They replaced the rear differential bearings and assured me that would fix it. Hopped on the highway to get home and within 30 seconds heard the exact same noise. I don't know what to do at this point do I just live with it or does anyone have any advice?

Just a recap I hear the noise when lightly touching the accelerator at highway speeds. It's almost a humming noise. If I lift off the gas to let it coast it goes away instantly and if I push the gas harder it goes away as well. You only hear it when cruising at highway speeds with with the accelerator held at a specific speed.

I'm running out of ideas and going crazy. Could it be a leaky exhaust gasket? Could it be my tires even tho it disappears right when lifting off the gas? Any help is greatly appreciated

getafewliv

Sounds similar to my old Durango, had to replacethe pinion bearing in the rear diff.

Left it for a few weeks and it got louder and louder. Started off very subtle.

speedstar

iTrader: (5)

i have a similar noise i've been hearing lately between speeds 30-90+mph coming from the rear
the faster i go the louder/faster it gets

not a constant "humm" but more like a "Mmm Mmm Mmm Mmm"
(car is an 06 rwd 350, slammed)

ashawn6841

@getafewliv I believe that's what they just changed. It sounds like the noise is coming from the driver side front but I do realize noise in a car resonates and travels so take that with a grain of salt.

getafewliv

My bad, missed that.

Kd0t

iTrader: (17)

Normally, I would say get a transmission fluid flush but with the ISx50s our transmissions are sealed shut.

Maybe look into changing your rear differential fluid?

Good luck

Edit: didn't see you had it done already.

synrgy350

Yes but remember that BG developed an adapter to allow our transmission fluid to be exchanged using their PF-5 machine. I had this done to my IS350 at the dealer a while back, the transmission was definitely smoother, especially after 100K on original fluid. I also had the differential fluid replaced as well, despite it being "lifetime".

getafewliv

(sorry for off topic) What did they charge you for the transmission fluid? I am at 110,000kms and debating on doing this or waiting.