Is this what a broken flexplate sounds like?

[Blind]

http://www.youtube.com/watch?v=OmtdbnflVtI&feature=youtu.be

Back story -
Basically, transmission went out, lost 3rd/4th. It was on the freeway when this happened and my wife told me she couldn't pull over (no break down shoulder) so she put it in 2nd and drove until the next exit, before she could get to it the engine stalled, and she threw it in neutral and rolled the truck to the offramp and into a gas station. AAA towed it home, let it sit for 6 months and I pulled the trans and had it rebuilt.

Got it back together, fired it up and I get this noise.

~1.5 years ago I replaced the top end with all new parts due to a cracked head -
062 vortec heads
stock 1.5 rockers
stock pushrods
MPFI conversion (clogged spider)

Truck has ~120k miles.

I pulled the belt, same noise.
Pulled the valve covers and adjusted the valve lash on all the (stock GMPP) rockers, same noise
Pulled the inspection cover and unbolted the 3 torque converter bolts and slid it back out of the way, same noise. With it pushed all of the way off the flexplate hits it slightly as I can see rub marks on the face of it now after trying that. So is the flexplate wobbling?


I haven't pulled the transmission back off yet, because pulling the tcase off and putting it back on is a pain in the balls. But looking for ideas. Failed lifter, cracked flexplate...?

It doesn't sound like rod knock that I've heard in the past, it's too regular/constant. I drove it a little bit after this video and gave it WOT up to ~4k rpm and the sound was the same the whole way up, it's hard to tell but I think the noise at idle is louder now.

 

[BHBurban]

Yeah, kinda like a rod knock. or a constant rattling.

 

[Tempted]

Have you changed the exhaust manifold gaskets?

 

[Blind]

Have you changed the exhaust manifold gaskets?

the ones to the block were new with the heads, the donut gaskets look fine, I pulled the Y pipe off to R&R the trans, and again to remove the inspection cover from the bellhousing. When I did the 2nd time I did introduce an exhaust leak on the passengers side and it sounds different from the noise in this video..like an exhaust leak, not a bolt in a pair of pants banging around in a dryer.


it doesn't sound like a rod knock to me, it's too regular, I bought one of my track cars with a spun rod bearing and it sounded completely different, much more "tinny" sound that echoe'd through the exhaust which this does not do.
http://s40.photobucket.com/albums/e237/blindbatts/97gt/?action=view&current=MVI_1560.mp4

 

[badazzbulldog]

what does that have to do with the noise its making?

 

[Swims350]

my old man had a cracked flywheel do the same thing, constant knock never changed, sold the car, guy who bought it put in a new one and drove it back to my old man's telling him about it.

 

[badazzbulldog]

did she over-rev the engine in second gear? how far did she drive in second gear? when it was towed home did you run it then?

 

[Blind]

did she over-rev the engine in second gear? how far did she drive in second gear? when it was towed home did you run it then?

She doesn't remember but she did say she kept it around 55mph, so I imagine that's around 4500rpm. With it stalling at that rpm I bet something in the transmission overheated and locked up.

I ran it once it was dropped off by the tow truck to get it into the driveway, it was making this noise then but I just figured it was something in the transmission bouncing around. I'm kicking myself for not inspecting the flexplate when I had the transmission off...

 

[badazzbulldog]

with the t/c moved back from the flexplate can you see any cracks around the bolts to the crank? one other thing how is the oil pressure? also with it running put the tip of a screwdriver to the oil pan and your ear on the handle to see if the noise is loudest in the pan

 

[Blind]

pressure is fine on the stock gauge (~60) and with the valve covers removed oil shoots out of the pushrods pretty good on both banks.

it's so loud underneath that I can't tell any difference with my mechanics stethascope. I can't see the flexplate bolt center very well at all, even with a high powered flashlight. The holes where the t/c bolts go through all look fine.

The only thing I really see is rub marks on the face of the t/c (freshly painted as it's new) from running it pushed back and unbolted from the flexplate, and the flexplate does look to wobble a little while it's at idle, grabbing it and yanking it around I can't really make it move.