QuestionQUESTION: Model: Hyundai XG 350 L, 2005, 36 k
I hear a noise like "shaaaaaaa" at low speed to about 50 MPH.
I don't hear that noise when the car is stopped at "P", "N", or even "D" position. Noise comes only when the gas pedal is applied during the car is moving, and it completely disappears when I release the pedal. Also it disappears when I change from "D" to "N" while driving. I asked a mechanic, but didn't get clear answer. Do you have any idea about this symptom? I seemed to read that a trouble in an electric circuit (a solenoid?) could cause such a noise. Is it a good idea to pull out all the fuses and relays in the fuse box and re-mount those one by one? Is any caution to doing that? Thank you so much.
ANSWER: You've already established that the noise is in the transmission or engine area. You won't be able to hear solenoids in that area at speeds of 50MPH. You have some sort of mechanical noise.
Most likely, it's in the transmission. First, I'd like to know whether the noise varies with engine speed or vehicle speed, and whether it goes away when the transmission shifts to a certain gear.
When I say the noise varies with engine speed, I mean that it's frequency will go up as engine speed goes up, and down as engine speed goes down. A noise of this type will increase in frequency as you accelerate up until the next transmission shift. At that point, there will be a sudden drop in frequency, and the frequency will begin to increase from that point as you continue accelerating.
When I say the noise varies with vehicle speed, I mean that it's frequency will increase as your MPH increases.
Don't worry about doing anything electrical at this point. You've already given me enough information for me to know that this noise is not electrical in nature.
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QUESTION: Thank you so much for the prompt and kind answer.
Concerning the noise frequency, the noise seems NOT vary with the engine speed. However, it is clearly heard at low speed and becomes faint at higher (I'd better to correct to up to 40 MPH.) Probably due to louder external noises? Or it may disappear at 4 or 5 gear. I don't feel any shift shock. I appreciate once again.
AnswerMost likely, it's coming from the transmission, maybe from the differential in the transmission. If that's the case, it may even be normal, depending on the noise level. You'll need to have it checked and get a good opinion from a knowledgeable, honest, and competent technician who can actually hear the noise. Since they'll be familiar with your particular vehicle and it's normal noise levels, I'd recommend taking it to a trustworthy dealer. You've provided me a good explanation of the noise. If the noise is apparent, this description should suffice. If you think it may not be apparent, ask to have a technician or service advisor ride with you so they'll understand what you're talking about.
