something rubbing underneath after exhaust install

[mstevens]

Well I recently bought a 2000 gmc sierra 4x4 5.3, i was driving and original exhaust broke at the mid pipe, so i bought a flowmaster cat back for it, and ever since ive had a very annoying rubbing/ grinding noise coming from somewhere underneath. At first the muffler was rubbing the driveshaft, i ended up shifting the exhaust over to prevent any further rubbing, now i can't even push the exhaust over far enough to touch the rear shaft.. But i still have a rubbing noise going on and its driving me nuts!

 

Any suggestions/ ideas greatly appreciated!

[govener71]

Pictures?

[mstevens]

Only have the one picture underneath right now.. Seems to be enough clearance between the two.. Maybe I need to make more haha

[govener71]

Have you checked where the y pipe meets your cat back? The two bolts that connect there might be a little loose and causing a rattling noise with so many vibrations while the motor is running. I had it a few months ago where one was a little loose and it sounded like a squeal but when I started tapping on my exhaust I could tap right to where it was coming from.

[mstevens]

Checked today, they were a little loose, so I tightened them with no change :/ thanks for the idea though, anything else come to mind?

 

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[Bad Bowtie2]

Check the air pressure in your spare tire?? Make sure it's tight up to the truck's frame....

 

(just another idea)

[mstevens]

Tire pressure is good, but it's not by any means tight to the frame, I can spin it move it side to side etc very easy, so I tried to raise/ tighten it to the frame with slight improvement but it's still pretty loose, even though it's tighter the noise/rubbing remains unchanged, any other ideas? It feels like right front passengers say they can feel it beneath their feet

 

 

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[Chris]

Mine was either the hangers or heat shieds. I went through it after the engine swap

 

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[Silverado4x4]

Check the heat shields that connect to the body for the exhaust, it maybe touching and what your hearing is not a rubbing noise but the exhaust (air) noise transmitting from the exhaust to the body from the heat shields.

[mstevens]

I think that did it, the heat shield under the passenger side floor was touching the cat, took a pry bar got it out of the way hopefully that gets rid of my noise! Thanks for the replies guys

 

 

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