broken torque converter... WTH???

[Longhorn Man]

So the longhorn has been making a noise for a while.
OK, for QUITE a while.
A knocking sound. You know the kind, the kind that makes you hang your head low, gives you a sickening feeling low in your gut... the kind that makes you avoid the freeway at ALL costs...
Yeah, that sound.
So a few months ago, I realized the sound kinda seemed like it was coming from the tranny. The tranny was just rebuilt 14 months ago... I *THINK* it has a 2 year warranty... it's all good. I'll look at it later.
So THEN I see the flex plate is bent.
Hmmmm.... I'll bet that sucker is cracked! So i order me up a flex plate, then go on a trip to get a suburban, and then the Longhorn becomes project back burner... like I could neglect it any more than I already do.
So I pull it into the shop yesterday to swap out the flexplate... shouldn't take too long right? A couple nuts and bolts here, a shaft, and badda bing badda boom it's done. Right?
So When I hit one of the converter bolts with the impact, it zips off... like it is supposed to. But I noticed the flex plate.... flexed.
What the heck?
Then I notice the converter moved a little. No way they are still bolted together.
But... I only unbolted one bolt.
Anyone ever seen this happen before? 2 of the mounting lugs broke off the converter... causing a WHOLE lotta clanging and banging... but mostly... the knocking sound I have been nervouse about for quite a while.


But wait... it gets better!

I had the tranny rebuilt by a semi-local cat... pretty well known guy, does outstanding work. I dig out the papers on it.
hmmm, lets see....
rebuilt november 24th of 06.
Hmmmmm
Waranty.... parts and labor....
one year
DOH!
So i got the tranny in the back of the burb, the burb on salty roads ( :cry: ) and headed over to see the guy tomorow after work. I mentiooned that it's been making the noise for 6 months or so (yeah... I'm THAT lazy/buisy) and he said they MIGHT be able to swap it out for free... but told me to bring 45 bucks just in case.
And the longhorn is sitting.



At least it wasn't the engine knocking huh?

[Ol'Rover]

yeah, yer lucky lol. To bad the longhorn ahs to sit in the snow

[Slammed70]

Yes, Ive had that happen. The bolts were loose. And allowed just enough play for the converter to move back and forth enough on accel/decel to eventually crack the "ears" on the converter. Im willing to bet that the knocking noise you heard was the "ears" on your converter getting banged around by loose bolts.

And why do you have a BOP tranny? You running a 455 or something?

[wibilly]

never had the ears break off but a long time ago when i was young i had a 69 camaro with a pretty healthy 350 and a powerglide i used to twist up pretty regularly and it was always spitting out the converter bolts. sure beats a new rotating assembly for that caddy

[Longhorn Man]

they weren't loose. It was hell getting the bolts off. The impact wasn't strong enough to bet one of them... I had to lock the flex plate and use a 1/2 inch breaker bar.
Plus, there is no damage on the holes on the flex plate, no mushrooming, no oblong holes... nothing.
The knocking was the converter moving around and smacking the mounting lugs that were still bolted (tightly) to the flex plate.

[shortbus2]

I've seen quite a few of those broken lugs. I work for a leading converter/tranny manufacturing company http://www.coanracing.com/.
We sell a street/strip bop converter that uses the same factory style lugs.
If you get a new convertor like your old one, weld down each side of the lugs. The factory welds are crap/weak. Also the pilot "the numb that goes into the crank" is welded on. It needs 4 small tacs under the lip that goes into the crank. Make sure the tacs are up in the groove and not larger than the diameter of the pilot. Blue locktight on the bolts

Make sure the tranny guy replaces the pump bushing,seal and checks out the pump gears.

[Longhorn Man]

Good eye on the BOP thing. This is a TH350 with a TH400 converter bolted to a caddy 425. I considered an aftermarket converter, but I need a stock stall RPM, and.. well, I'm trying to put my money on the burb right now.
I'll defenatly inspect the welds,a nd if they are as you describe, have them welded up. I use locktight on just about everything... that or antiseze compound.
I will be double checking the pilot diameter too.
Good info, and thanks for the insight.
My tranny giuy says he hasn't seen this in many many years, and figured it was a faulty converter. One lug came apart, causing added stress on the next one.
I'm just wondering how long I was cruising on one converter bolt.
The whole tranny is in the back of the burb right now, he wants to inspect it and replace the seal and bushing.

[89 crew]

I haven't broken the lugs but I did break the neck off of a 400 converter with a 400 small block. It made quite a mess throwing all that oil out.

Were the bolts too long? Maybe they helped push the lugs away from the converter?

[truckdude239]

umm wow is all i can say

[Longhorn Man]

good question... but, the bolts were provided by the converter company.
I joke that the cad motor has so much torque that it was ripping them off. But everyone knows that is total BS

[FleetsidePaul]

You went on a trip to get a Suburban?

[Longhorn Man]

lol! Yeah, it was kinda kept on the hush hush.

[truckdude239]

Originally Posted by FleetsidePaul

You went on a trip to get a Suburban?

umm how did you mess that we even had t-shirts

[Longhorn Man]

he didn't miss it, I talked to him while I was on the road. he's just messin.
Paul.. I did miss when you told us what was in the safe though.

[fine69]

Don't worry Andy. Your tranny guy will fix it.

[truckdude239]

andy oi know i was messing to

[Longhorn Man]

kewl.
And mike... I knew my tranny guy would take care of me, and he did.
Totally SUCKED dumping out that mobile one tranny fluid this evening, and sucked even more pouring in 11 quarts of fresh mobile one. ($$$$) There was too much brass shavings to reuse the oil.
But, I drove it home from the shop this evening, no knocking banging or clanging.
Sweeeet!

[longhorn70gmc]

Don't feel bad Andy, Mine is sitting to for now. I broke the positive wire and the starter went bad. I just got my new one in from Kragen. I am so glad I kept the receipt from seven years ago. I don't mind changing it out so much and waiting when there is free in the replacement. I am starting to notice that the parts places don't carry allot of our parts anymore or they have to order them. Hope your tranny swap goes well for you.
Billy

[bryanw1968]

Originally Posted by Longhorn Man

they weren't loose. It was hell getting the bolts off. The impact wasn't strong enough to bet one of them... I had to lock the flex plate and use a 1/2 inch breaker bar.
Plus, there is no damage on the holes on the flex plate, no mushrooming, no oblong holes... nothing.
The knocking was the converter moving around and smacking the mounting lugs that were still bolted (tightly) to the flex plate.

I fear I have the same thing going on with the '68. About 6 months ago I started to notice that same knock you describe. It sounds like it's coming from the convertor also. I also notice that the flywheel wobbles a little when it's running. I checked the convertor bolts and they were a little loose so I tightened them back up but the noise is still there. Fortunately I'm about to go to a 2004r and a new 3000 stall but I'll post what I find when I pull it apart.

[70rs/ss]

Too much torqu from that caddy 500!! (didn't read the the whole post 425) The diesels will do that if you have a stock set up and start with the tuners, exhaust, etc, etc. so the BETTER converters are made with a billet plate and the lugs are cut out of the chunk. It your case I might add a tack or two to each of the new lugs before fluid. Ask the tranny guy to do it (or if it will hurt the clutches) that will keep it from happening again. Good luck. Again didn't read the whole post, especially the part about it being back together already!!

[Longhorn Man]

I asked him about adding some weld, told him I have an awesome welder guy that could do just about anything... he said he strongly advises not to do that.
So I filled the converter, popped it in the tranny and stabbed it.
Felt nice haulin down the freeway this morning on the way to work and not hearing it banging and wondering if it was a rod ready to exit the block or something.

[70rs/ss]

Originally Posted by Longhorn Man

I asked him about adding some weld, told him I have an awesome welder guy that could do just about anything... he said he strongly advises not to do that.
So I filled the converter, popped it in the tranny and stabbed it.
Felt nice haulin down the freeway this morning on the way to work and not hearing it banging and wondering if it was a rod ready to exit the block or something.

I wondered about the extra heat. Maybe it was just a bad converter?? Good Luck!!!

[Palf70Step]

Glad to hear our favorite Longhorn is back to being mobile again!