today i went for a little drive i never got on it hard or anything and was only gone for about 15 mins. When i got back in the driveway i noticed kind of like a rattle/knock noise.

i used a stethoscope and listened all over the block, oil pan, valve covers and dont hear anything unusual. i got under the car and it sounds like this rattle is coming from the torque converter area.

at first i thought it was coming from the oil pan but with the stethoscope i dont hear anything bad there.

this rattle only happens at idle or very low rpm. when i give it some gas even just a bit to maybe get the car up to 1500rpm the noise completley dissapears and is not present at any higher rpm. I put the car in park and other gears and its there except when i give it gas and get the rpm up a bit.

i took the cover off the torque converter and the knock got even louder so im thinking its something in the converter that is going?

i noticed nothing unusual while driving. shifting seems normal. i dont know enough about how the torque converter works inside but is there any checks i could do to at least tell me if it is the converter or something else.

thanks for all the help.

 

Make sure all of the converter bolts are nice and tight.. when they get loose it can make noises like that.

 

well i checked the bolts and they all seem to be tight. this rattle is really loud when its in that certain low rpm.

i don't know too much about torque converters but is there something inside it that could cause this. it sounds almost like a bolt or something rattling around inside it but as soon as you just touch the throttle it goes away.

maybe its not even the converter. is there anything else around there that can cause this?

also it kind of feels like i can feel this rattling on the floor under my feet.

 

cracked flywheel

 

i tried moving the flywheel and torque converter with my hands and i can actually shake them back and forth slightly. not much but a little play. im sure there shouldn't be any play there correct?

can a cracked flywheel only make noise in low rpm.

another thing i will add is that when i went on the drive today there was no noise at all and then after only a 15min ride is when i started to hear it but at this point it wasn't all that loud. i could barely notice a slight knocking noise and another guy that was here could barely hear it. Then when i was looking at it in the yard for about 30 mins basically it just idling and me giving it a few shots of gas trying to figure it out it got noticeably louder and now its a really loud rattling noise that anyone would notice.
so basically all within an hour it went from no noise to a really bad rattling noise.

another thing i will mention is that about 2 years ago now my starter blew up. There was a huge bang and the casing cracked and a chunk fell off. im just wondering if this could have possibly put a slight crack in the flywheel way back then and now that crack has just opened up more.

I just took the car out for a drive and it works fine besides the noise, the engine sounds good, oil pressure good and it shifts fine. seems 100% normal so at least im sure its not anything to do with the engine.

 

could be a flywheel... and yes there are parts inside of the torque converter than can come apart. if it does though one of the things you would want to check it the trans fluid.. also.. if the Torque converter does come apart on the inside.. it will waste the trans in short order.. lots of chunks of metal fins everywhere.

 

i checked the trans fluid and it looks ok. its not black or anything, looks normal. i really doubt anything came apart in the torque converter since whenever i give throttle the noise goes away and there is no shifting problems.

 

im having the same problem any more input would be great

 

Sounds to me like one of your cats is rattling. With the engine cold, try and smack the cats with your open palm, you'll have to smack it pretty hard. Let us know.

 

My car had the exact same problem with the exact same symptoms. If the torque converter bolts are tight then it is most likely a cracked flywheel. Mine cracked on me a little while ago and just changed it. Take the inspection cover off the converter again and look in between the flexplate and engine. Look for ANY small cracks. You can rotate the flywheel with a wrench on the converter bolts. Go all the way around and look.

Here is the crack I saw when I took the inspection cover off.


Here is the flexplate after I got it out.


As you can see, that little crack I saw while it was on was actually a huge crack going around to every bolt. Mine had the same sounds/symptoms you are describing. After 2000 RPM it seemed to fade. I would take it easy until you know forsure what it is incase it is the flexplate.

 

yeah mine is the flexplate have not tore it apart yet but it looks like the bolts came loose

 

I just finished my new 396 stroker and have less-than 100 miles on it. I don't have it apart yet, but it appears the flexplate bolts to the crank hub are loose. I can feel slack between the flexplate and crank when I try to rotate the flexplate and torque converter with my hands. The torque converter is tight on the flexplate.

I used new ARP 12 point flexplate bolts (PN 200-2902) and a new TCI internally balanced SFI approved flexplate. The bolts were torqued to 70 ft lbs w/ ARP moly lube under the heads and thread locker as I recall. So, I'm not sure just what went wrong here? I know the torque was correct on the flexplate bolts. Hopefully, I can tell what went wrong when I get it apart.

Has anyone else had this same problem with an LT (the flexplate bolts loose) with only a few miles?