LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Cracked flexplate symptoms?

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Old Oct 27, 2009 | 06:32 PM
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Default Cracked flexplate symptoms?

Ticking/clanking coming around the inspection cover/torque converter area during IDLE.

Strange dull noise on deceleration of revs in park.

When putting the car in D and holding the foot heavy on the brake there is a horrible vibration coming from the area when giving it gas up to 900rpms. At the same time the ticking/clanking seems to disappear.


Does this sound like a cracked flexplate? The guys at my local shop say they "dont see" a crack. Yet have a nice bill ready for me to have a rebuilt engine installed because they think its a piston wrist pin.

97 Z28 A4
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Old Oct 27, 2009 | 08:50 PM
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Anybody?
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Old Oct 27, 2009 | 09:04 PM
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Sorry i dont have an answer for your question. But how much did this cost to get checked out? Too much to take it somewhere else and get a second opinion? If you sense any "funny" business at all, i would take it somewhere else to at least make sure.
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Old Oct 27, 2009 | 09:25 PM
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They charged me $35 bucks to check it out. I think they just listened to it and checked the converter bolts. Supposedly looked at the flexplate. I plan on taking it somewhere else later this week.
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Old Oct 27, 2009 | 09:33 PM
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Heres what I would do, I would remove the inspection plate, unbolt the torque converter push it back. Then grab the flex plate and move it back (front of car to back of car) and loose play Id say its a broken flex plate.

I broke one not to long ago and it made a lot of tinny knocking noise.
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Old Oct 27, 2009 | 09:52 PM
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x2 do the work yourself and grab that **** and jerk it around like its your joy stick,lol..
if its broke it will wiggle around and it should not...
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Old Oct 27, 2009 | 09:58 PM
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Ok guys I'm going to do that Thursday when I get off work. Heres a video off youtube that sounds a lot like the noise I'm hearing. But its only for the first 20 seconds or so when the car is idling. The noise doesnt get louder like the one in the video. http://www.youtube.com/watch?v=wtK_I...eature=related
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Old Oct 28, 2009 | 12:39 PM
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I can't see the vid, but from what you're describing it reminds me of the when mine cracked on my 77 cutlass. Couldn't see the crack, couldn't move the flexplate, until it was out of the car, then you could see a hairline crack off one of the converter bolts about an inch long. If you're good you can swap it with the trans in the car, but it's not too much fun. good luck, hopefully it doesn't cost you too much....
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Old Oct 28, 2009 | 02:21 PM
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Yes I'm praying its the flexplate and not internal engine issues. I'm going to put up a video tonight of my car on here.
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Old Oct 28, 2009 | 05:25 PM
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If you need a replacement, try TCI p/n 399173.
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Old Oct 28, 2009 | 10:11 PM
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If its the flexplate I will look into the TCI thanks!

OK here are some videos I took today (sorry about the crappy quality)

This video is with the car warm and you can really hear the noise when the camera is under the car http://www.youtube.com/watch?v=gEkk7xrIgO8

This video shows the bad pulsing vibration that seems to be coming from under the console/ flexplate area when in D with the foot on the brake and raising the RPMS to 900 http://www.youtube.com/watch?v=BJf8j_JXTko

*The noise isnt as loud in these videos vs real life due to a shitty camera*
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Old Oct 29, 2009 | 06:27 AM
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I was just thinking....How about when you first engage the starter, and it's beginning to take the load of cranking the engine. Are there any unusual sounds at that point, just before it starts? You know, creaking or crackling sounds, indicating a "flexing" flex-plate....
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Old Oct 29, 2009 | 10:31 PM
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Originally Posted by leadfoot4
I was just thinking....How about when you first engage the starter, and it's beginning to take the load of cranking the engine. Are there any unusual sounds at that point, just before it starts? You know, creaking or crackling sounds, indicating a "flexing" flex-plate....
Yeah I noticed there is an odd sound thats intermittent when starting my car.
Its a creeking metal type sound thats kind of hard to describe. Anyway, my mechanic listened to it today and said it sounds like a flexplate to him and hes going to look at it for me on tuesday while I'm at work. He said you have to pull the transmission to replace it. So I imagine labor cost are going to be fairly high.
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Old Oct 30, 2009 | 06:37 AM
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Originally Posted by Chris97z
..... He said you have to pull the transmission to replace it. So I imagine labor cost are going to be fairly high.

I do all of my work "flat on my back", with the car on jackstands. Therefore, while I don't have to "pull" the tranny, I do have to disconnect both it, and the torque converter, in order to access the flexplate. Most shops will do this on a lift (lucky guys!) and indeed "pull" the tranny out of the way.
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Old Nov 3, 2009 | 10:47 PM
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Okay guys get this!

Looked at the flexplate and its not cracked at all. All the bolts are tight as well. Mechanic says I should try putting some regular 10w30 oil in it and see if that helps. Since my problem started after using the 0w30 German Castrol. He also said my engine mounts are done for and causing the vibration.
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