violentgod1

How can i tell if the flex plate is cracked or broken and if so how do i go about replacing a flexplate in my 92 rs LO3 camaro. I still have the one off of my 89 LO3. Are they interchangable. Any and all information on this topic would helpful. Thanks all.

IROC_385Z

they both should be a neutral balanced 1pc seal plate...if they are the same size and look the same then they should be interchangeable.

What makes you think that the flexplate is even broken? I've managed to bust a few and it always sounded like a bad rod-knock upon decelleration.

violentgod1

that is exactly what it sounds like. Whenever i let off the gas i hear this loud knocking that is running with the rpms. Im not positive that it is that but when i gave the symptoms on here it was the first thing anyone said. How hard is to replace or what do i have to do to replace it.

IROC_385Z

best bet is to:

Remove starter (disconnect battery first)
Remove the 6 bellhousing bolts
Remove the 3 bolts from the TQ converter-to-flexeplate
drop the tranny (carefull of the detent (kickdown) cable, dont break it!)
Remove the 6 bolts holding the flexeplate to crank

100 bucks says its busted right around the hub that bolts to the crank...thats where all mine broke. "Flex" the flexeplate and you will see the crack run almost all the way around.

If you need one I have a TCI 153 tooth for a 1pc that should fit...it was from a 350 but they are both internal balanced and it'll fit. I broke 2 stock ones before installing the TCI and now have over 450 lb-ft and it is fine...so far...

AlkyIROC

Under normal conditions to change the flexplate, the tranny has to come out. With a few modified or special tools, it might be possible to remove it without pulling the tranny. It depends how far back the torque converter will go into the tranny and if you can get a wrench onto the flexplate bolts.

Trying to find a shortcut may be more headaches than it's worth. Just pull the tranny to change it.

violentgod1

I pulled out the engine and tranny on my 89 camaro but that was last year and dont really remember alot. Is that all there is to it. Isnt there the transmission lines and disconnect the driveshaft. I dont remember it just being that easy.

AlkyIROC

Sure if you're going to pull the tranny then everything needs to be removed from it to pull it out. You could cheat a little bit. Disconnect the driveshaft. Unbolt the torque converter. unbolt the bellhousing bolts. Support the tranny and unbolt the tranny crossmember. SLide the tranny back far enough on a floor jack to get at the flexplate bolts. The shifter cable will allow movement back. You may have to disconnect TV cable and the cooler lines might have to be disconnected. The tranny doesn't have to move back a lot to access the flexplate bolts but pulling it right out is the best.

violentgod1

i just got out from under the car and beside breaking 2 dust shield bolts(dammit) i looked at the flexplate and it wasnt broken from what i could see but there was def a dec amount of unusual wear on the teeth. Will cause the same problem and what would cause just one side of each tooth to wear really fast. It just looks like on about half the flex plate that a side of each tooth is grinding on something.

IROC_385Z

then it is broken. When you decellerate it is letting the cracked half of the plate "flop" around and hit ****. If the plate is still connected then man-handle it a bit: grab the perimeter and pull it/wiggle it to see if it moves in ways that it should not.

violentgod1

i went out and got under the car and tried moving it and what not and really there was no play. I can tell that is where the knocking is coming from. Is it possible that the plate is off balance. I didnt see any sort of crack at all. Could it be broke a little bit near the center bolts where i wouldnt be able to see it but enough to make it vibrate so it hits something. Stupid car.

IROC_385Z

"Could it be broke a little bit near the center bolts where i wouldnt be able to see it but enough to make it vibrate so it hits something. Stupid car."

Thats EXACTLY where it is probly hiding...may have to get it off to see it. Just take it off and get a new one. If you have a strong motor get a thicker flexplate. Also be sure to thread-lock the bolts so they don't loosen up...once I thought mine was broken (that would have been the 3rd time) but it really was just loose at the converter. I still replaced it with a TCI just for peace of mind, which is what I would recommend for you to do too.

violentgod1

what do you mean by thread lock. Def dont have a strong motor. Just got the stock LO3 with a super competition hooker exhaust. It sounds pretty good though. Thanks for help.

HorseflyDF

I have the same knocking sound.
Ive been under the car several times and
cannot identify it even when it starts shaking
and knocking.
The tranny shifts fine and the engine runs strong.
I may have the same problem with the flexplate,
Im running a 350sbc with about 300lbs of torque.
I never had a problem starting the car either.
Would think if the flexplate is cracked it would get
worse untill it broke completely because of torque
required to start the engine.
Also its an intermitent sound.

Dropping the tranny was my next alternative.
Im looking for a shop to do it that tranny is heavy.
thanks
for sharing this info on the flexplate.

IROC_385Z

Threadlock is something you buy at the part store...its comes in a tube and you put it on the threads of a bolt and when you torque the bolt down the threadlock will harden, "locking" the bolt in place so it can't vibrate out.

Yea, those trannies can be tough to wrestle down alone.

HorseflyDF

The previous owner did this swap 350sbc.
Its a goodwrench truck engine with loads of torque.
I looked again after I started her this morning,
I can see the flexplate and converter since there
isnt any cover and she has a wobble in there.
If I had my own garage I would try to tackle this job
but I dont think I want to do this one in the street,
after all I would have to get the car up at lease 18 inches
off the ground.
sucks duty big time
I dont like people I dont know
working on my car had many bad experiences here
in Nyc.

IROC_385Z

Ew...got any car-buddies with a driveway or garage even? It IS a bitch to do, but it can be done with a good jack, some bricks and jack-stands.

Good luck, however you do about it.

HorseflyDF

I dont have any car buddies hehe
all my car buddies are on here.
Actually I could use my brothers back yard
he doesnt have a garage either but its off
the street, he said he didnt mind although hes
hen pecked so he might get some chit from his wife.

I was thinking about going to home depot
and getting some 8x8 wood I already have some
4x4 which I used to get under the car.
Figure get up on the 4x4s the on to the 8x8 that
would be high enough. I might try to do it.
Im a crazy bastard when it comes to my car.

IROC_385Z

LOL, sound like *crazy bastard*. Just don't let the car fall on you...I'd hate to think that you let a flexplate be the end of you!

GOOD LUCK AND BE CAREFULL! Let me know how it turns out.

And if you need a flexplate, I have a TCI 153 tooth for a 1pc rear seal (87+ 305 and 350) that only has under 5000 miles on it...I had to get a differant plate for my 383 so this one needs a home.

HorseflyDF

Im pretty sure I have a 2 piece rear
at least thats what the info I have so far
from the block number says. Goodwrench engine
made in Mexico. didnt come with tacos though.

I dont know the about how many teeth yet.

I really want to put in a 4 speed superT10
I dont need a T56 speed I think thats to much shifting.
and the T5 I heard sucks for 350.
but that swap is not easy to do either in the street.

Ill try not to let the car fall on me.

That would probably hurt alot.

Red|ine

I've got a 350 right now and i'm putting in a t-56 because i just blew up my t-5. t-5's arent the most durable

Go with a t-56, you only use the 5'th (and even 5'th) on the highway, unless you're a speedy bastard, too.

HorseflyDF

yeah thats why I would like to have a T10 rockcrusher.
cause I got some rocks I need to crush also.
but they only came in early models
82-83 maybe.

I did some research here and found its hard to find
a Supert10 in a grocerey.
and its alot of money like the t56 is alot of money
also maybe like 2Grand. T5 is cheap so thats why it breaks.
Only put a T5 in your car if you want to break down
on some lonely road and walk home and maybe even get
raped or something like that.

Im not really crazy by the way.