Anybody else have this happen? I went out and started my truck (07 F150 5.4) Tuesday. Walked back in the house while it was warming up. When I came back out I could hear a faint knocking sound. I began trying to track it and the noise led me to the oil pan. Naturally I freaked thinking this was a sound from the engine. I gently revved her to 1800rpms and the noise disappeared. As engine speed slowed the noise reappeared around 1300rpm and was considerably louder at idle. I called RobertP and ask him about it. He suspected the flywheel. Had me place the truck in gear and the sound went away. Put her in neutral and the sound reappeared. Reverse no noise. He confirmed it was a cracked flex plate and sent me a link to a better built flex plate. It's made by PRW. Thanks again RobertP. Here's the link. http://m.ebay.com/itm/161060375315?nav=SEARCH&sbk=1
Not sure why this happened. Fatigue? Went racing weekend before and posted my best times ever. The stock flex plate seems thin to me. Robert mentioned this happening to stock trucks as well. Anybody else?

 

Old thread for sure But,

Did you get this sorted?

 

Sure did. Installed the new flywheel and went to the track and ran the 12.3@110.9. Great part! Easy fix. Just slide the trans back about 6".
Labeled the stock cracked flywheel with it's fastest time and speed before breaking and hung it on the wall lol.

 

Thats very impressive. I would do the same thing and hang it in the garage XD is that flexplate the same for 4x4's?