The 40 Mph Humming Noise

[jesterlives]

:chairshot:

This is extremely frustrating so I am hoping someone can help me. I cannot think why this noise occurs except for maybe the speedometer cable. Here is what happens....while driving, a fairly loud "humming" or "high pitched whining" sound occurs from the moment I hit about 39-40mph and it continues until I hit 43-44 mph. I notice the sound more when accelerating versus slowing down but it occurs at both times. It is loud enough in the cabin that even with the radio playing fairly loud, you can still hear it.

I have no idea what this issue could be and would rather get an idea before heading to the garage for repairs. I also need to get the oil gasket replaced because I am also getting plum size oil spots on the drive now. I had the car up on a friend's rack and tightened the bolts on the crankcase...it did stop the oil leak for awhile but it has returned now.

I look forward to some ideas so I can get both these issues repaired at the same time! Thanks.

[bongt]

I think I have the same problem with yours, you can hear a humming sound wen acceralating. I was going to try and clean for some carbon deposit as suggested (will wait till I do the chg oil). Keep us posted.

[jesterlives]

I am scheduling an appointment with the dealership where I bought my car...only because I get free oil changes as part of the deal. (it is not a lexus dealer). I am hoping to find something out. I will keep you up to date. I will check my oil and see if it is tied to the oil leak. I know someone wrote of the pil leak issue in another forum...they provided helpful information on getting that fixed.

[Grumpa72]

I would try and eliminate as many areas as possible. First, check ALL of your fluids: PS, transmission, differential, etc. Then, I would rotate your tires using your preferred method. The next thing I would do is to check the tension on your belts.

I have found that speed-dependent sounds can often be caused by low fluid in the PS or transmission as well as a tire that may be excessively worn or have a broken belt in the tire.

[LexRexBlue]

I don't think you want to hear this. I had the exact same problem at the same speed. When I noticed it I had Lexus look. They didn't find it, but they heard it, too. They changed all kinds of parts. No luck. Eventually, it was determined (about 3,000 miles later) that it was the transmission. I had been insistant that they find the problem because I knew the long term warranty was going to run out. They replaced it for free.