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It was the flex plate - now, how bad is it?

470 Views 13 Replies 7 Participants Last post by  DieselPro
Previous thread: Can anyone help me identify this CATASTROPIC engine noise?

As @DieselPro mentioned quickly after I made the post - it was the flex plate making that awful engine noise.

I started by pulling the torque converter cover, which the flex plate had made a deep groove on the inside of.

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After sliding under I immediately saw that at least 4 of the 6 bolts on the flex plate obviously wasn't torqued to spec (66ftlbs), because I could turn them by hand. A couple of them had almost worked their way halfway out already.

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So, how did the flex plate bolts undo themselves? I don't know.

A couple of years ago the old starter went bad, so I swapped it out with this ...

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... sold by a local importer. They didn't advertise it as original GM, but not as a Chinese knockoff either.

This is what it looks like today, attached to the block (I have never shimmed this starter).

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The starter support bracket has always been secured to the block. I suspect that the starter, not being authentic GM or shimmed, worked it's way wrong into the flex plate. The damage visible on the flex plate teeth is only on the side towards the starter gears.

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The way I see it, I have a few options.

The most expensive one being swapping both the flex plate and the starter.

What would you guys do? Is it possible to just tighten the flex plate bolts back to specs and possibly shim the starter?

I would greatly appreciate your two cents!
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Never use shims under a 6.5 starter. If the starter requires shims get one that doesn't. Use the red Loctite and lots of it. Make sure the replacement flex plate matches the old one . > teeth and counter weight. Thanks for the recognition, sometime I feel like Rodney Dangerfield here. "I get no respect". :)
Are you serious about the red Loctite?
Thank you for clarifying on the Loctite.

I knew this was the case for the Service Position on the later model hood hinges, but didn't find it to be the case on the older '88-'00 models. Is it supposed to work on those, too? If so, do you have a photo? I looked for quite a while, trying to convince myself this was the case last fall, but didn't see a way to do it.
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