Does this sound like a cracked flex plate to you?
 

Long story short its a LS swap into a C4 corvette with a 4l60E, external cooler and a 3500 stall. I felt a shudder and heard a sound like rocks in a can. I put it in N and coasted to a stop. I didn't hear anything so I put it back in gear. I was able to make it home with no noise. It was fine so I thought.The next day the rattle is permanent. It only happens in gear.

Have you pulled off the cover to inspect it yet?

There is no cover like old school trans it has a round 4" or so access. I pulled it and inspected it and don't see anything. I need to pull the starter and take a look from that side. I have a feeling its going to be a little while before I can do It. We are expecting, I just found out today the Dr. scheduled the birth for Thursday. Time to put the Vette on the back burner:thumbs:

Congratulations!

Thank you sir :cheers:

Ive have a cracked flex plate sound like that AND Ive also had loose converter bolts sound like that also! Good Luck and CONGRATS!:cheers:

Congrats - on the baby, not the noise.

Thanks guys :thumbs: (on the Baby not the noise) :D
I droped the exhaust today the convert bolts were not loose I took them off, pushed the converter back and I still don't see any cracks. I guess the next step is pull the trans when I get some time. Cross your fingers.

Some flex plates have quite large weights welded on them if the converter is out of balance or there is a bit of play on the thrust bearings and the crankshaft moves ever so slightly that could be the noise. oh don't forget to check your starter have seen some hit by the ring gear ( look for shiny spots on the ring gear and starter gear face)
I am leaning 80% to torque converter as the cause and 20% to flex plate crack or warped. It is fairly rare for a flex plate to fail, a out of ballance or failing torque converter may be the cause.

So be prepaired to replace the torque converter if the flex plate is not cracked there are moving parts in there you don't want to remove the transmission twice :thumbs:

Good luck :cheers:

I'm hoping its a flex plate. :(
Its a built trans and $700 converter.

.......... There is a difference between LS and Gen 1 & 2 Torque converters ... not sure what exactly ... pilot ? ... Is yours LSx specific ? .............

yes, ls engine trans and converter.

1 more bolt and the transmission is out ..We are going to find out soon. :willy:

Fingers crossed...

you're too fast. wanted to tell you,when i pulled my trans,a $5.00 harbor freight transfer pump sucked most of the fluid out through the filler tube for minimum mess.

Well its not the flexplate and nothing was loose. I got the trans out and the flexplate looks great.To the trans shop they go. Circle-D is right down the street lets hope he can fix the converter for me.

I found the problem.. converter is full of shavings and you can see what I think is part of the clutch.:confused2:

http://ls1tech.com/forums/picture.ph...ictureid=94103

:ack::ack::ack::ack::ack::ack::ack::ack: :ack::ack::ack::ack::ack::ack:
Well i suppose it is time to disassemble the auto trans and clean it out,
would have to look at the fluid flow diagram to see where it goes from the converter. Good thing you had a good look at the torque converter :thumbs: Hopefully you will be back on the road very soon :cheers:

Hopefully, I have the trans in the back of my Jeep right now. Today is a 14hr day for me so sat I'm taking the 80 mile trip to drop it off with my buddy and next week I'm dropping off the converter at circle-D he is about 15 minutes from my house... :D

The shiney outside ring adjacent to the Green/yellow line: is this where the oil pump bolts are hitting the convertor? Gonna need a pump too.

:cheers: I found drinking heavily helps to reduce sticker shock when paying the bill.

Have someone else drive as drivers that drink and cry are more dangerous than women drivers sober...:D