700R4 Knocking?

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yer welcome, MarshMonster~:~

Group: alt.trucks.chevy Date: Mon, Oct 25, 2004, 10:51pm From: snipped-for-privacy@excite.com (Jason S) I have a 700R4 that seems to be knocking. When I start my truck I hear a light knocking sound from the area of the torque converter. The noise is there all of the time no matter what gear the transmission is in When shifting from park to reverse the noise stops for about one second but that is all. The noise does not get any louder when you rev the motor, however it does get faster as the RPMs increase. With the truck on a rack you can hear the noise coming from the torque converter. I have unbolted the torque converter from the flywheel and then started the motor. There is no noise with the torque converter unbolted from the flywheel. I have looked at the flywheel and it does not seem to be cracked. Does anyone have any information on this knocking sound? Thanks, Wayne ======= ======= The flywheel is cracked.

yer welcome, MarshMonster~:~

Yep, and just so you know they like to crack around the bolts(hard to see with the trans still in there, but possible with a flashlight:)

cracked flywheel

or the bolts could be loose

Thank you for your reply. I failed to mention in my post that I have already removed the transmission and have given the flywheel/flexplate a good inspection and do not see any cracks in it. All of the flywheel and torque converter bolts were very tight.

Thanks, Wayne

I think the 700R4 has a anti clunk spring, and if so, it might have broken. There are others that read this newsgroup that know way more than I, perhaps they will chip in on this suggestion. Rick

did you take it off the crank and magna-flux it ?

even a tiny crack will make an unGodly amount of noise

I agree with no bull it has to come off most cracks are hidden behind the bolts.

what's the cost of a new flexplate as opposed to the cost of magna-flux?

Good point!

I work at Louisiana Weld Test. Magna-flux, P/T, or even X-Ray does not cost me anything. Don't knock someone's actions until you know the whole story. :-) Anyhow, I am installing a new torque converter today and hoping for the best.

Wayne

We werent knocking anyone. The guy brought up a good point for someone that may not have the luxuary of getting free magnaflux service. Cheaper just to by the flywheel. Did you pop off the pump and have a look see inside it to make sure it is ok?

replying to Jason S, Ron wrote: Mine Knocked for a Year or more.....I tried to back up the other day and it barley pulled.....So I drove it home and now it don't move.....tearing into it today....I thought it sounds like the Torque Converter. ...