speed-dependent chuff chuff chuff sound from front end

[StealthyBlagga]

My '98 4x4 XLT 4.0, with 66K miles, makes more "road noise" than I'd expect.

There is a "chuff" sound that seems to happen once in every wheel revolution, resulting in a continuous "chuff chuff chuff chuff" that increases in frequency as vehicle speed increases, and gets less and less frequent as the vehicle draws to a halt. I can also feel a subtle vibration coming through the vehicle body in time with the chuffing.

The sound is independent of engine speed, happens with the wheels pointing straight ahead, and happens even with the transmissions in the neutral position, so it seems to be wheel/axle related.

Above ~20mph, the chuffing sounds seem to merge together into continual "road noise", but is getting noticably louder over time.

Anyone have any ideas ?

 

[jimbo74]

it sounds like it is either driveshaft related, shock related, and or wheel/tire related.... what kind of tires do you have on it? are the shocks still original? what kind of "chuff"? is it a metallic type scraping, or does it sound like something is rubbing somewehre?

 

[dogfriend]

Check your front tires at the outside edge for feathering. I have the same problem. I'm 90% sure it is the tires. The first time I noticed it, I rotated front tires to rear and the noise mostly went away. Now the noise is back because the fronts (used to be on the rear) have picked up the same wear pattern.

I know that others have had this problem also.

http://www.explorerforum.com/forums/showthread.php?s=&threadid=58865&highlight=tires

 

[X~FACTOR]

Do you have brand new tires? I remember when the shop put mine on they did not take off the sticker on one of the tires and as I drove away there was this chuff sounds you were hearing. As I go faster the chuff becomes increasingly faster as well.

 

[StealthyBlagga]

Thanks for the quick feedback. Here is an update:

I checked all the tires (Goodyear w/~10K on them) for pressure (OK @ 26psi cold) and wear (all even). All the wheel nuts were tight. I then pulled off the front-left tire and examined the hub/suspensions, but found no obvious problems.

Next, I reinstalled the tire and spun it by hand (transmission in N)... I could hear a very faint "shhhhh" sound in the same range of rotation, covering maybe 1/3 of each tire cycle. I still couldn't see anything rubbing on/near the wheel, so this may reside in the axle/front diff.

The vehicle is overdue for a 60K service, so I will have the diff fluid checked for level and contamination, then have it changed if necessary. I will also have the tires rotated. Anyone have any other suggestions ?

Thanks

 

[StealthyBlagga]

OK guys, here's the scoop...

The front diff fluid was OK. However, rotating the tires appears to have solved the problem (at least for the moment). Easy fix if it lasts.

I haven't had the chance to spin the wheel by hand to see if the "shhh shhh shhh" sound is still there. Of course, this noise could have been a complete red herring. I'll post again if the problem returns.

Thanks for the help.

 

[98GT-40P]

I'm a little concerned about running only 26psi (unless you're an off-roader). You're generating alot of heat on top of already blazing daytime concrete here.