QuestionQUESTION: My 2002 hyundai Santa Fe ,V6 2.7L automatic transmission AWD, vibrates only at 38-40mph.Seems to happen in normal shift mode,4th gear,slight uphill grade.Ceases upon acceleration,or manual downshift into 3rd.No steering wheel vibration.Trans. serviced,still there. Tires fairly new.Not noticed when accelerating quickly,like highway on ramp.
ANSWER: Let's get a little more specific. You say that there is no feeling of vibration in the steering wheel. Do you feel it through the seat, or is it making other parts of the truck rattle? Or, do you mainly sense it through your ears, by hearing the low frequency of the vibration? And, even though you say it doesn't manifest in the steering wheel, does it affect the ride or handling? Also, how many miles on the truck? Let me know and I can be a little more help.
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QUESTION: It has 136000 miles on it.It's a physical vibration, not just audible.The whole vehicle vibrates. It's like driving over rumble grooves,or really rough pavement.Doesn't affect handling.
Answer I would suspect that an out-of balance tire is the most likely cause of your problem. A front tire would probably show up in the steering wheel, but a rear one wouldn't. This could be caused by a weight falling off of the wheel ass'y or a tire fault such as a cut belt or cupping.
However, while doing a little research, I came up with a rather disturbing report on rear suspension failure that I suggest you look into by taking your truck to a front-end shop and getting them to look it over carefully. Check out: http://www.consumeraffairs.com/news04/2008/07/nhtsa_santa_fe.html
