Over the past 5000 miles or so, I've developed a new noise. It sounds like a loose heat shield rattling. My trans dipstick tube was loose, so I temp zip tied it in place to make sure it wasn't rattling on anything. That didn't help. I can't find anything else loose.
Here's the specs. 01 7.3 420K. Can't hear the rattle or noise at idle, or with the hood popped and ranging through the rpms. Can't hear it under heavier acceleration. Mild acceleration, and or maintainin speed is where it's most prevelant. While driving, it sounds like it's more towad the passenger side. Is it possible that the EBPV is coming apart and rattling around??

 

If your sure it's not an internal issue, rather a down the road issue. Take a sledge hammer and nail each tire and listen for the rattle.

You have four chances to isolate the approximate location.

Grab your creeper and start from the nose and start hanging on everything that dangles. A broken exhaust clamp hangar will look good but if it's sheared, that would sound like you described. You might want to manhandle your exhaust outlet and see if you can shake the noise alive.

Denny

 

There's a heat shield above the muffler under the bed. Mine rusted out on one end and was touching the exhaust. That was the cause of my rattle.

 

Mine sounded like a chain dragging. Found a smashed soda can blowing around in the spare tire

 

Starting to lean towards a cracked flexplate. will do more investigation over the weekend.

 

I'm not sure if you have an aftermarket exhaust but there's not much room as the pipe passes by the transmission. I've had to re-adjust mine a couple of times as it shifted and started rubbing against stuff around there.

 

My experiences with cracked flex plates on other engines has been more of a knock than a rattle, but never heard a 7.3 with a crack. Try power braking stopped.

Also try getting on a down hill and coasting with the engine off to see if it's still there. Bang and tug on everything underneath, I'd start with the exhaust system. Some have a catalytic converter, those can rattle at different loads if the internals are busted, mufflers can do it too.

 

Also try having someone else drive and sit in different seats. The direction of noises in a vehicle can be very deceiving and changing location can often pinpoint the actual direction.

 

When you shake the crap outta your ex wife, and all you hear are marbles rattling around up there..thats a cracked flexplate(at idle).....the downpipes' a good thought. Buddys' aftermarket was riding against the fuel banjo bolt.

 

Well, something happened, and the noise started happening at idle. I grabbed my metal rod that I use for a redneck stethescope and climbed underneath. It reallt pissed me off (and made me happy) to find a loose exhaust pipe. I was under there days ago, shaking the crap out of the exhaust. I did the beat on the tires with the sledge to see if I could hear antyhing, and nothing. I must've hit a bump just right to knock it loose enough and stay loose. Thanks for all of the ideas. I'm just glad it's a $12 clamp versus pulling the trans.

 

can't beat a cheap fix.