Hello all,

I've got a mystery noise that I can't figure out what it is.
Here's what I can tell you:

1. The sound seems to coming from the left (drivers side) front quadrant

2. Only happens between 25 and 35 mph.

3. The sound is most noticable at the 25 and 35 mph thresholds (accelerating and decelerating).

4. Noise sounds like a muffled "rumble strip" that lasts between less than a second and a few seconds.

5. Noise is of low enough volume, that it would drowned out by the noise of the heater fan or radio if not paying attention. Noise not immediately obvious to passengers unless pointed out to them etc.

6. The sound happens intermittently but repeatedly. It is not constant.

7. There is no vibration felt. (at least not that I can feel from the drivers seat etc)

8. Happens whether or not vehicle is accelerating or decelerating.

9. Makes noise regardless of whether I'm coasting, braking, or pressing the accelerator.

10. Makes noise regardless of whether the transmission is in gear or coasting in neutral.

11. I've looked unnderneath for anything really obvious but I'm obviously limited by my own limited experience and expertise. (a good manual is never a substitute for expertise gained by hands on experience etc (no matter how smart I think I am etc))

12. Steering/turning, and going up or down hill make no difference and have no impact to frequency or quility of the noise.

13. Noise happened before and after new tires. new tires different type than the old one. same noise etc.

Any suggestions, ideas, thoughts, advice, counseling, etc etc etc.. would be greatly appreciated.

Thanks,

Thomas

 

ABS sensor?

 

Is it from inside the cabin or under the truck?
I'm not sure what a rumble strip sounds like, but maybe that ambient air temperature sensor inside the dash.
Its a little fan (behind those slots) next to the dimmer rheostat (for controlling the brightness of the interior lights).
You can open the access panel, and stick your finger in the fan or some other small object. Its not spinning fast so it won't hurt you.

Mine makes this annoying ticking sound..

Just a suggestion

 

a rumble strip are the ridges that they sometimes put on the side of the road, or before you get to a pay toll, to wake you up. When your tires go over them they make a noise and makes the whole car vibrate.

the noise is coming from under the truck...

how would I check the ABS sensor? just see if it's loose?

Thanks for the suggestions so far....

THX,

Thomas

 

Anyone else have any suggestions or ideas?

 

Do you have SAI system? If so perhaps one of those valves. Could unplug SAI wiring to test, might set codes.

ABS sensor is part of the wheel hub. Not sure how it might work itself into contact with the sensor ring.

 

I don't have Secondary Air Injection / SAI....

I don't know much about how they test wheel alignment in a shop etc.
I'm really spit-balling here, but I'm picturing they put all four wheels on rollers and run the vehicle at a moderate speed to test and adjust etc.
If that's the case, I wonder if listening while standing next to the vehicle, while they're running it on the rollers, might help isolate/locate the source of the noise?

Sanity check please....

 

am I off my rocker with the above idea?

 

The fact that it doesn't change with acceleration, coasting and such and only happens at that mph is a head scratcher. Any way to put a camera on the dash/floor/seat to capture it so we could hear?

 

The alignment process does not use rollers and does not require the vehicle to run at all. Targets are mounted to each wheel and cameras pick up these targets. The targets have precise geometric reflective shapes imprinted on them which the cameras track the position of. All of this is done on a rack after initial calibration (runout compensation and caster swing).