Blown Ford

Got a 4.75" long crack in my flex plate. Making to much power for it lol. Happened 2 days after I went drag racing. Impressive to say the least. I always thought the stock piece was flimsy.

papa tiger

Ouch ! But still lucky, no main brg. cap or rod blown out. LOL

dr_bowtie

No that means the Torque Converter is Ballooning and flexing the flex plate....that or the thrust washers on the crank are taking a ****.... you can measure end play off the crak to make sure its within spec...

If you're thrown boost at it you might want to step up the converter to a one with Anti-Balloon plates

Blown Ford

I have a built trans and a Circle D stall converter with a billet case. Mike Troyer thought this might happen with the recent track times. When I installed the trans and converter back in 2010 48,000 miles ago I remember thinking how flimsy that flex plate is. You can flex it with your hands. It's only 2.3mm thick. Not much to it. It cracked 2 days after the race. Hadn't driven the truck since driving it home that Sunday. Went out, cranked her up, went back in the house while she warmed up, and when I came back out there was the popping sound.

Blown Ford

Installed this new flex plate today. It's from PRW. Nice piece. SFI 29.1 certified. Cold rolled premium steel, 4mm thick almost double the stock thickness, cold welded ring gear is welded in 9 places on both sides verses just 8 welds on one side for the factory part. Weighs 7.9lbs verses the factory plate at 6lbs. Not bad for $79.

chris.c

Back when I had a Lightning we had a convoy of trucks driving back to DFW From KCMO from a national event when one of the trucks just quit running and wouldn't restart. Turns out he completely broke the flexplate. Center hub tore free from the rest of the plate near the crank bolts pretty similar to the location of yours. Crazy thing is it just broke while cruising down the highway.