Odd Noise Avalanche and Tahoe.....

[swathdiver]

Next time the truck is idling, listen to that right cat up close, maybe give it a tap or two with a hammer. Same with the third one (if you have it) in front of the muffler.

 

[David Smith]

Next time the truck is idling, listen to that right cat up close, maybe give it a tap or two with a hammer. Same with the third one (if you have it) in front of the muffler.

I have never heard it at idle, but I will get under it and check for loose bolts/hangers and bang around on a few things.

 

[swathdiver]

I have never heard it at idle, but I will get under it and check for loose bolts/hangers and bang around on a few things.

I'm thinking a piece of honeycomb in the cat has broke loose. Might only move around when you're on the road though as you described but worth a shot.

 

[David Smith]

I'm thinking a piece of honeycomb in the cat has broke loose. Might only move around when you're on the road though as you described but worth a shot.

Would it be loud enough to hear in the cab though? It only makes noise right around 50 mph. It does it on smooth roads too...

 

[swathdiver]

Would it be loud enough to hear in the cab though? It only makes noise right around 50 mph. It does it on smooth roads too...

Maybe, if its just a walnut sized piece it can bounce around, get jammed in place and then bounce around again with no rhyme or reason. That's not all it could be though. Could be a bolt, exhaust hangar, a door fastener, etc.

 

[David Smith]

I got somewhat of a video...with the road noise it is very hard to hear. skip to about 20 seconds and turn your volume up with headphones in. Let me know what you think...if you can even hear it.

 

[swathdiver]

I heard it but not sure what it could be from that.

 

[David Smith]

I heard it but not sure what it could be from that.

It is so hard to hear, but in the truck you can hear it pretty well. It only happens from 45 to 55 mph. I am going to try and get under it soon and shake a few things around. It is supposed to rain for the next 5 days, so I will have to wait for a dry day.

 

[swathdiver]

One thought that crossed my mind when I heard that noise was u-joints. Have you pulled and inspected them yet? Those speeds are about when the truck gets into 5th and 6th gear and the driveshaft begins spinning faster than the motor.

 

[David Smith]

One thought that crossed my mind when I heard that noise was u-joints. Have you pulled and inspected them yet? Those speeds are about when the truck gets into 5th and 6th gear and the driveshaft begins spinning faster than the motor.

Not, but I will check them for abnormal wear or play when I get under it