anyone ever crack a crank? kinda long

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blacksheep

New member
SO I just got done with a tranny rebuild the night before and was only able to put about 5 miles on it(finished at 3am). So i go to work the next day and at lunch I fly home and get her out. the trans shifts real nice, no complaints. I didnt have a chance to do a launch because she has been sitting for 3 months, and I didnt bring my labtop to make sure all was good. I did stand on it a few times and it was shiftin mucho harder(as expected). now im driving down the main drag and noticing alot of rubber-neckers and I must say I was feelin dam good, maybe i jinxed myself. this was my 1st tranny build and it took forever cause lack of time and researching where to buy parts and who NOT to buy kits from. so I was picking a friend up and no sooner then leaving her parkin lot i hear this tick. at first I was thinking it was my a/c compressor because it usually makes noises. turn that off. tickin is getting louder. im like WTF, maybe something in the dust cover?? I got about 75ft and it now started to sound baaahd. I whip into a lot and kill it. I sat there thinkin what i could have forgot in the trans. well I thought I messed the tranny up so for shits and giggles i try to start it again. wont start, acting like the battery was dead(click,click). I tow it back to my shop and take the belt off and try to start it again. oh my f-ing god. it would start and run but ive never heard such a sound from a engine. sorta like i left a wrench in the crankcase sound. so i pull the dust cover off and notice i can move the converter back and forth about 2inches from the bottom of the flex. I also notice my balancer isnt moving. sorta in disbelief i unbolt the converter and slide it back a little to get a better look at it. well the flexplate isnt cracked, nothing wrong with the balancer either. my only question is if i coulda missed something in the trans to damage the engine (like the trans locked up for a split sec)? Its hard to believe not 10 miles after i rebuild the trans from hell that the crank would crack.... just another day in disneyland :drinking:
 
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Lynn D. Brown

New member
Torq C

Torq C

2" sounds like a helluva lot of play in the TC. I'm thinkin' it maybe should be able to move ¼"-½". In fact if it was still bolted up, it shouldn't move at all ! Did U make sure that it had clicked all the way back into the tranny pump when U installed it ? Usually about 2-3 clicks ?

Once, before I knew better, I tried to force a TC back by tightening on the Trans mount bolts, but fortunately I stopped and asked guys on the Internet. I hadn't gotten it to click all the way back on the pump. Sometimes it's really hard to get it to click all the way back. I had to turn and jiggle the damned thing for 5-10 min.

If U don't get it all the way seated on the pump, I understand U can trash the tranny pump. Don't know if that's your problem.

Didn't understand your comment that U could move the TC 2" from the "flex" ? What flex R U talking about ? As far as the engine, try moving the engine around by cranking on the flexplate teeth while U have the TC disconnected. The damper should be moving also - then U know whether your crank is together.
 
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blacksheep

New member
I could move the flexplate back and forth(direction it spins) about one inch each way from the bottom most part of the plate. This was when it was unbolted. The balancer wasnt moving when i did this. When i first discovered this(still bolted together) i assumed it was the crank and went for a drive(anger management). I called a few buddies and one of them said he has broke his flexplate on his 4.3 a number of times when he was wheeling. He also said the noise was horrible. So I went back to my mess and further examined it by unbolting it, prying with a screwdriver, and getting a better look at it. To my dissappointment the flexplate survived. It still amazes me that the crank must have sheared at a angle because it would still run. I also drained my oil and put it through a paper filter and i didnt find much/any metal at all. I am guessin that it sheared in a journal and thats what kept it all together.
 
TurboManiacal

TurboManiacal

Donating Member
I'm still curious about the bolts themselves. That's what my problem was/is. Look more closely at how the flexplate is attached. Mine problem sounds exactly like yours.
 
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Lynn D. Brown

New member
Wrong Flexplate bolts

Wrong Flexplate bolts

I had some good ARP FP bolts from Conleys' and when I cranked on them they wouldn't go all the way in. And we had cranked on them a bit. Hope we didn't screw up the new Crank threads. These bolts also had a threadless gap at the top that was wider than the Flexplate thickness - so it never could have tightened on the plate even if it hadn't bottomed out !

Then we find out that they were the wrong bolts - they were for a FLYWHEEL. So therefore much longer and w the gap at the top.

We were ready to lift in the motor, so I have time to order new ones. Fortunately O'Reillys' had some from Mr. Gasket - much shorter and no gap at the top. But they don't look as strong. They had washers w them, so we used them - not sure if I should have ?
 
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