Strange Russeling Noise

plinkie · July 24, 2007

2000 gmc Sierra 5.3 373 gears. I have never heard any noise like this in any vehicle. When towing the boat on hi way for half hour or more, there is a strange russeling noise, like dry leaves or newspaper being crumpled. Now, the noise cannot be heard while driving above 60 kms hour, but if I slow down when I get to a city or town, the noise starts up just while accelerating. It does not sound like it is coming from the engine. You can hear it coming from just below the cup holders and ashtray area of the truck. When truck shifts from 1st to 2nd, the noise quits during the shift and starts up again until you hit speeds of over 60km. then seems to disappear. It almost sounds like it is coming from firewall area in center of truck. This only happens when towing. I tow in 3rd and use tow haul. This noise is very noticeable. Please let me know if anyone has ever encountered this problem. Thanks

bobcat5544 · July 24, 2007

2000 gmc Sierra 5.3 373 gears. I have never heard any noise like this in any vehicle. When towing the boat on hi way for half hour or more, there is a strange russeling noise, like dry leaves or newspaper being crumpled. Now, the noise cannot be heard while driving above 60 kms hour, but if I slow down when I get to a city or town, the noise starts up just while accelerating. It does not sound like it is coming from the engine. You can hear it coming from just below the cup holders and ashtray area of the truck. When truck shifts from 1st to 2nd, the noise quits during the shift and starts up again until you hit speeds of over 60km. then seems to disappear. It almost sounds like it is coming from firewall area in center of truck. This only happens when towing. I tow in 3rd and use tow haul. This noise is very noticeable. Please let me know if anyone has ever encountered this problem. Thanks

Does the sound speed up the faster you go or is it constant no matter what speed you at.

plinkie · July 24, 2007

2000 gmc Sierra 5.3 373 gears. I have never heard any noise like this in any vehicle. When towing the boat on hi way for half hour or more, there is a strange russeling noise, like dry leaves or newspaper being crumpled. Now, the noise cannot be heard while driving above 60 kms hour, but if I slow down when I get to a city or town, the noise starts up just while accelerating. It does not sound like it is coming from the engine. You can hear it coming from just below the cup holders and ashtray area of the truck. When truck shifts from 1st to 2nd, the noise quits during the shift and starts up again until you hit speeds of over 60km. then seems to disappear. It almost sounds like it is coming from firewall area in center of truck. This only happens when towing. I tow in 3rd and use tow haul. This noise is very noticeable. Please let me know if anyone has ever encountered this problem. Thanks

Does the sound speed up the faster you go or is it constant no matter what speed you at.

Thanks for the reply. No, the volume of the noise nor the speed increases. Sounds like someone sitting under the ashtray, crumpling dry leaves.

Starrman · July 25, 2007

sounds to me like detonation (spark knock...pinging)

Try the next step higher octane gas next time you tow and see if it still does it

vortec22 · July 25, 2007

Do any of the heater core hoses run in that area? I've heard sounds kinda like that from air bubbles getting pushed through the cooling lines before. Just a thought/guess.

plinkie · July 30, 2007

I am just wondering if there are any trani lines that run close to the firewall, as the noise quits momentarily when truck shifts from first to second, then I can hear it again until I get just past the 60km range. If I take off the tow haul for a minute, noise seems a bit quieter. Seems to be transmission shifting that regulates the noise. It is not a tapping noise or anything even close to a mechanical noise, but more like russeling leaves. Really weird. I guess I won't worry about it as everything seems to be running fine, but if anyone has ever had a similar problem with their truck, I would appreciate hearing from you.

99silveradoz71 · July 31, 2007

I had air in the heater hoses that come through the firewall that was causing a gurgling that would decrease in intensity when the truck shifted

plinkie · July 31, 2007

Air in the lines sounds very close to what this sounds like. I will check a little closer and maybe get someone to stick their head down there while I am driving (even though that might look a bit funny from passer by's).