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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: lukieg on September 08, 2011, 09:30:36 am
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Hello all.. I have been reading this forum for some time and I am in need of some help. A while back I put a 427 tall deck into my c10. I had some issues with the starter at first which caused me some grief and likely grief to the flexplate as well.. A few days later the bolts came loose and thrashed it yet somemore. Its mated to a stock 700r4, I pulled back the tranny and removed the flexplate.. no cracks and it seems straight. Started the truck up.. the thrashing noise is gone.. but I can still here a steady.. sometimes intemittent tap from what seems to be the torque converter area. This motor wasn't a rebuild.. and its treatment is unknown.. it is from a top kick and was governed.. also when i was scrubbing down the block to freshen it up with some paint,.. i noticed the intake was blue.. and block was black.. old crate engine perhaps? The oil pressure is good and steady... oil comes out so clean its odd.. starts and runs well.. and the noise only happens when in gear and goes away when you drive.. I'm so confused..I think I can see a small wobble in the flexplate as its running,.. but everything works as it should.. starter doesn't bind or fluctuate.....I'm at a loss.
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Do you hear it at idle in gear or while driving? It could be the torque converter. My brothers rattles and sounds like the radiator fan hitting its shroud when you accelerate hard.
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It does it when in gear but goes away under acceleration, trans is working properly. Thanks
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Loose torque convertor or cracked flexplate would be my guess... My 85 sounds just like you describe. I will be tearing it down soon to replace the transmission as the current one doesn't have second gear and I bet my flex plate is a goner as well..
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Thanks for the quick reply... I checked the flexplate a few times.. and tightened it.. the flexplate isnt making contact with anything that would cause the noise.
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it might be the coming from the starter as when i put my 366 talldeck in my c30 the teeth of the flywheel would hit the ring near the cap of the starter which caused a ticking i hope this helps you out if its not that someone else will tell hopefully help you out
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Thanks for the quick reply... I checked the flexplate a few times.. and tightened it.. the flexplate isnt making contact with anything that would cause the noise.
If it is cracked, it will flex and the crack is what is making the noise. You won't see a crack unless the transmission is a couple of inches away. I take old starter bolts and instead of removing the trans I will slide it back, which makes it easy to reinstall.
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I checked it for cracks... I thought it may be the starter too... but upon closer inspection.. its fine.. there is however a small wobble in nthe flexplate..its an intermittent tap however.. when i put a screwdrive to my ear.. i can hear the tap through out the engine.. but it sounds like its comming fromn behind.. maybe a bit closer to the starter side.. but nothiung appears to be making contact.
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The flexplate in question is used.. got it from a junk yard... i know the odds are stacked against this one. It just stumps me.. i pulled the carpet and insulation to fix and rock guard the floor.. i find it lasts better with the salt... so any noise from the engine seems amplified.. im baffled. thanks for the quick replys.
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I like the starter bolt idea.. i'll use that next time..
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It gives all the sypmtoms of a bad flexplate.. but the only apparent damage is a slight warp.. which doesnt appear to make contact with anything but does wabble slightly..I just hate it... i know this was a ghetto swap but I still like to take pride in my builds..noises are annoying.
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flexplates are so inexpensive, i'd never put a used flexplate in with unknown history
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I replaced the flexplate with a new one... the old one didnt have any cracks... So after I replaced it.. I started it up.. the starter didnt grind which was a bonus.. then after a few seconds it made a horrid noise and I thought something was destroyed. I shut it off.. turned it back on and no horrid noise.. but still the intermittent tap when in gear and a vibration which it had previously around 1000rpm. Prior to the swap the transmission (700r4) was a bit sloppy but otherwise fine. Im very confused by all this. I had the starter shimmed maybe its moving the noise closer to the flexplate.. However it seems to have room. Im at a loss.
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it might be the coming from the starter as when i put my 366 talldeck in my c30 the teeth of the flywheel would hit the ring near the cap of the starter which caused a ticking i hope this helps you out if its not that someone else will tell hopefully help you out
Sir.. I applaud you.. thats exactly what it was.. i removed the ring.. which I hope ok.. haha and it got rid of it.
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Never Mind... Its still there.. It must be the torque converter...stupid question but Im broke.. can I stick a th350 or 400 one in there?
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you can but need to drive shaft length will not be the same and you will need to send a vacuum down
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not the whole transmission... just the TC.
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no they are of a different size 350/400 use a 10" or a 13" while your 700r4 uses a 12" plus the splines are different
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I feel stupid... im pretty bad lifter ;D