SOLVED: 2004 Suburban metal noise underneath engine

Maintenance/Repairs
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@insightful, @kurtwm2010, @Barkydog, @GeorgeSanJose, @the_same_mountainbik Turned it into the garage today. Showed the guy one of the videos and he instantly said it sounds like a cracked flywheel (he called it another name when requesting the part price though). He was going to throw it on the lift and confirm it before dropping the transmission. I checked the u-joints and heat shields. All were fine. I will let you all know what it ends up being for sure later this week. I appreciate all the help and insights. - Keith

1 Like
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He may have referred to it as a “flexplate”, which is the equivalent of “flywheel” for automatic transmissions.

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I didn’t scroll back through the thread, but if I recall you mentioned something about damage to the ring gear that the starter engages. If that’s true, you’re going to want to replace this when the flexplate is changed. I’m certain the mechanic will suggest doing so. :relaxed:

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So I got the suburban back today. $900. Flexplate/flywheel replaced, 2 exhaust bolts fixed that had broken off, and a new drive-shaft with u-bolts. No more noise.

Thanks for everyone’s help with this!

Keith

2 Likes
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Glad to hear that you are back on the road and thanks for coming back and letting us know how you made out.

Those noises sometimes can fool a person.
I had a pick-up come into my shop that was diagnosed by another shop as a bad tranny. As the owner was turning into the shop
I thought that something flashed from under the truck and caught my eye. I got it on the lift and realized that one of the gas tank straps had broken. Each time the drive shaft rotated a counter weight would catch the strap
flex it and then the strap would be flung against the underbody making a terrible noise.

Yosemite

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Glad to hear you got the problem fixed. I think the shop probably means “u-joints” rather than “u bolts”.

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Were the exhaust bolts on the manifold?

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Only one bolt was broken on the actual manifold. No noise was coming from
there though. I verified that myself. The other bolt that was broken was
where the manifold connected to the beginning of the muffler assembly.