Flex plate or torque making noise? - Team Camaro Tech
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post #1 of 47 (permalink) Old Mar 25th, 20, 02:59 PM Thread Starter
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Flex plate or torque making noise?

I'm new to this so, take it easy on me


I have a bad clunking noise going on. At first I was concerned it was the motor but, I think it is the torque converter or in that area.


I put the car up on jack stands and I check the flex plate bolts. They were definitely not torque very high but, they were not falling off. I torqued them to 45lbs and re started the car. It seems less noisy but, it is still there.


I can grab the flex plate with my hand and I can rotate it back in forth about 1/4" and it seems to make the clunk I am hearing. It does not move front to back rather it rotates around the axis(as I assume it should).



Any ideas? I don't know how it bolts to the crank but that almost seems like the problem??


thanks,
Dave

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post #2 of 47 (permalink) Old Mar 25th, 20, 03:47 PM
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Re: Flex plate or torque making noise?

Flex plate should not move at all. It is bolted solid to the crank. If the crank isnít moving the flex plate does move. Not even a 1/4Ē.

Imo time to pull the tranny and change the flex plate.

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post #3 of 47 (permalink) Old Mar 25th, 20, 04:03 PM
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Sounds like the holes in the flex plate got elongated because they were loose. Like John said... Needs replacing.

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post #4 of 47 (permalink) Old Mar 25th, 20, 04:39 PM
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Re: Flex plate or torque making noise?

Flex plates don't move, and I doubt if the holes are all elongated the same to allow radial movement. Flex plates do commonly crak. That crack with time will cause it to blow apart so we are back to replacing the flex plate.

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post #5 of 47 (permalink) Old Mar 25th, 20, 06:17 PM Thread Starter
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Re: Flex plate or torque making noise?

Thanks guys everyone. The flex plate is brand new (500miles on it), I bought the car as is and I have e receipt where they had a transmission shop align the bellhousing and install everything so, I assume it was done correctly but, who knows.

I did look for cracks and I don't see anything. After I tightened everything, it seems to make a little less noise but, still makes noise. I will have to pull the transmission. This stinks, lol.. I have almost everything to do a T56 magnum swap but, I want this noise figured out before I introduce more issues.

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post #6 of 47 (permalink) Old Mar 25th, 20, 06:23 PM
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Re: Flex plate or torque making noise?

Assuming a shop did things right is a leap of faith I donít subscribe to.

Trust but Verify.
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post #7 of 47 (permalink) Old Mar 25th, 20, 06:39 PM Thread Starter
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Re: Flex plate or torque making noise?

Yup, I agree.

So, drop the drive shaft and then I can unbolt the flex plate and slide the transmission back. Any thing else?

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post #8 of 47 (permalink) Old Mar 26th, 20, 06:47 AM
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Re: Flex plate or torque making noise?

More than just the driveshaft......you need to drop the crossmember, unbolt the tranny from the block, disconnect cooler lines and TVS cable. Unbolt the flexplate from the torque converter and remove the trans.
Make sure you support the rear of the engine so you don't break the distributor cap or motor mounts.
I've never seen it but I bet the flex plate bolts to crank are loose or its cracked really bad - somewhat doubtful.

I have had a cracked flexplate before. No noise at idle but when you rev'd it up it sounded like a rod knock. Took it to 3 different shops in San Diego and they all diagnosed as a rod knock or wrist pin. Oil pressure was unchanged at all so I was skeptical. The fourth shop was a general repair shop and the old black man sitting in a rocking chair out front said "son...you have a cracked flex plate" as I got out of the car.
Sure enough there was a small crack in the flexplate.
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post #9 of 47 (permalink) Old Mar 26th, 20, 06:52 AM
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Re: Flex plate or torque making noise?

You need to unbolt the TC from the flex plate then pull trans & TC to be able to access the flexplate. whatever the noise source is, assuming its not from the motor, it is not involved with a T56 swap so if that where you are headed your current flexplate, TC, automatic trans will not be used
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post #10 of 47 (permalink) Old Mar 26th, 20, 07:18 AM Thread Starter
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Re: Flex plate or torque making noise?

Thanks again everyone! Looks like I got some work to do. Thank god for the quarantine! If I do get it apart and it is just the flex plate, then I will go for the trans swap.

Can I unbolt the TC from the flex plate and push it way from the motor and start the motor to rule out the TC and trans?

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post #11 of 47 (permalink) Old Mar 26th, 20, 07:41 AM
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Re: Flex plate or torque making noise?

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Originally Posted by evl ss View Post
can i unbolt the tc from the flex plate and push it way from the motor and start the motor to rule out the tc and trans?
no!!
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post #12 of 47 (permalink) Old Mar 26th, 20, 07:53 AM Thread Starter
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Re: Flex plate or torque making noise?

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Originally Posted by SoCal805 View Post
no!!
lol, ok. Glad I asked but, can I ask why? Seems like the engine would still be supported, just not connected?

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post #13 of 47 (permalink) Old Mar 26th, 20, 08:18 AM
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Re: Flex plate or torque making noise?

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Originally Posted by EVL SS View Post
lol, ok. Glad I asked but, can I ask why? Seems like the engine would still be supported, just not connected?
I haven't done it myself, but I have a friend that did it exactly for that reason on a 350 and had no problems. The shop I use suggested it to me, when I was trying to track down a noise myself, but it turned out to be a 3/16" hole in a header to head pipe gasket, sounded like a tick, but was just a leak forturnately.,
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post #14 of 47 (permalink) Old Mar 26th, 20, 09:20 AM
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It can be done. It mostly depends on how far your torque converter is already in the pump. I personally wouldn't be comfortable with less than a quarter inch gap. However this will take any stress off if your flex pate . That may make the flex plate sound go away if it is in deed the plate that is the problem. The flex plate can crack in many places. Most of the ones I have encountered have been cracked in the center where it bolts onto the crankshaft. Your problem sounds more like a bolt hole problem to me. I have been wrong before though. My wife reminds me of that often. Then I say , but I picked you. That usually changes the subject .
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post #15 of 47 (permalink) Old Mar 26th, 20, 09:52 AM
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Re: Flex plate or torque making noise?

If the flex plate is moving it has to be fixed. Whether or not the source of the noise.

Nothing to be gained by trying the disconnect the TC from the FP and starting the engine.
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