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th350 knocking sound

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Old 08-14-2012, 07:22 AM
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Default th350 knocking sound

hey there guys. i just finished my heads cam ls7 lifter swap. rebuilt the th350! now before i brought the trans down, i had the same sound but alot lower than now. i started the car multiple time for heat cycle of the springs without the trans and didn't have any knocking. i put the trans in took it out for a spin and when i stopped i herd the knock again. the knock comes and goes. i thought i was a lifter that's why i changed to the ls7, but its obviously coming from the trans. it only comes at low rpms once u raise it to about 850 it stops. iv seen many say its flex plate. let me know u guys experience or thoughts?? my uncle is telling me i did something messed up in the engine build? but i highly doubt it.
Old 08-14-2012, 12:44 PM
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none? no info?
Old 08-15-2012, 12:33 PM
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any info would be appreciated. will be bringing the trans back down today what should i be looking for?
Old 08-18-2012, 07:43 AM
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Sounds like the flex plate or the converter bolts hitting the back of the block...
Old 08-21-2012, 07:07 AM
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took the car apart again and found that the flex plate is not cracked, but i do see some wear on the bolt holes on that go to the crank. looks like it was rocking back and forth. bought new flex plate hope this solves my problem...



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