Knocking sounds at 65 to 70 MPH

mhc100g · 03-12-2009, 09:06 PM

Okay..this has got me completely befuddled.

I have a 2005 Excursion XLT all stock with new tires on it. I bought it about 6 weeks ago. About a month ago, something strange started to occur. At about 65 to 70 MPH I start hearing knocking sounds that literally sound like rocks either hitting the wheel wells or the undercarriage. There is no consistency when this occurs in terms of RPM, accelerating or braking or inclines or declines. It is a variable event. Sometimes the sound sounds like it is in the left front and other times like it is right outside my door. Occassionally it is on the passenger side or below the truck. Sometimes there is two in a row of varying volume and then it will go away for miles.

I have tried to isolate this as much as possible and the garage I go to says there is nothing hanging or loose in the under carriage.

Please help

hotrod94player · 03-12-2009, 10:47 PM

Go back to the place you go to and have them look at the axel bearings

militarydave · 03-13-2009, 02:57 PM

make sure that the wheel weights are on the wheels themselves. also, make sure no dust shield is loose inside the wheel!

-dave

louvel1 · 03-29-2009, 08:07 AM

I would love to know what it is as well because I have the same issue. I tend to hear the noise once the car has been running about 15 minutes after complete cool down. I took it to one mechanic and he said it is the natural tweeking of the car because of the size of it. He said I could try cahnging body bushings to polyurethane. I don't know if I buy that though.

cleah · 05-10-2009, 05:44 PM

I have a 2003 diesel. It has just started a rumbling vibration at 35 mph and 65 mph. Sort of a deep rumble that is clearly noticeable, but not harsh. There is no steering wheel rotation as would occur with warped discs. There is some vibratin that is best felt through the steering grip and peddles. I have had all four wheels re-balanced, but this made no difference. It feels more like a resonance of the type you would get with a rotating shaft in bearings, so I am worried about the rear axle. I checked transimissionand differential oils already.

Any suggestions please?

Clive