cracked flywheel?

[spence3203]

hey there my 99 gmc seirra with the 5.3 is making a metal on metal tinging noise. it's most noticeable when first starting out under a lot of torque but also does it a little when idling. the noise is coming from the bell housing and i've had 2 people tell me that its a cracked flywheel. I took everything apart and pulled out the flywheel but i see no noticeable cracks could it be something else? or could it be a non- visable hairline crack? are these trucks known for this problem?.....any help would be much appreciated

[Crmzendrgone]

Do you mean flexplate? Or do you have a manual trans. I doubt a flywheel would make a tinging sound.

[leolkfrm]

use developer, crack finder, around where it bolts to the crank. it's where iv'e seen them crack

[gmctrucks]

Just change it out there less than $30.00 dollars I say now that it's off you might want to also change out your rear main seal and any freeze plugs.

[spence3203]

It's called a flywheel in my book.... I understand it's a cheap fix but i don't exactly have the time or garage set-up to put it back together and take it back apart again if it isn't the flywheel that is broken. Can you give me some more information on the developer/ crack finder.... what is it? where can i find it?

[hotrodpc]

Hmmm, I have seen very light cracked flywheels and never even knew they had a problem. I'd think if the crack was bad enough to make a noise, the crack would be obvious. So I'd do as GMC says, change it out and anything else, like freeze plugs, rear main if easy to get to while there. Put it back together and if its fixed great. If not, I'd sure like to hope its not the input shaft bushings of the trans gone bad, letting the input shaft walk around. How does the shaft look to the trans? Pull the converter off since you have it all out and inspect the inside of the converter, and inside the seal of the trans for any obvious shavings or something that looks out of place. How about motor mounts. You say when under heavy torque, is something shifting under strain? Is maybe the starter gear getting lazy and not returning all the way back home, and make the gear is sitting close to the flywheel or barely tagging the flywheel. Or under torque the gear is sliding back into the flywheel. If it just tinging and not flat out grinding, I'd sure check that starter out too.

[hotrodpc]

Hey, spence, I just got to thinking, and yes I did have a buddy with this problem. I called him up, it was the starter. Now this was on a much older 350 Chev though and wasn't a high torque starter, but I say its still worth checking into.

[spence3203]

alright good info ..... thanks i will try to get the converter out but im not sure if i have room i didn't drop the tranny i only moved it back enough to get a ratchet in there and get the flywheel bolts out. i might have enough room to get the converter out but i'm not real optimistic. any suggestions on how i can test the starter?... the teeth are worn a bit but its got 154000 miles on it so the wearing doesn't seem abnormal.

[leolkfrm]

is the wear on the edge of the flywheel? does the starter have edge wear on the gear? could be a weak bendix allowing the gears to rattle

[spence3203]

guess i'll replace the flywheel since i already have a new one.....start 'er up and if she's still angry i'll throw a new starter in and hope it's not the converter
there is 65000 miles on the tranny since it was rebuilt. my boss had the same truck and had the tranny rebuilt at the same shop as mine and he lost it after 60,000.. (i'm a little nicer to my truck than i was to his) maybe it's time to start saving for a new tranny.