My flywheel was making a knocking sound a few months ago so i replaced it with a heavy duty flywheel. The noise went away after I did that.. Now about 4 months later the noise is coming back...

why? does it have anything to do with the amount of stress on the transmission from the huge tires?

basicly stock 4l60e w/ trail blazer torque converter and heavy duty flywheel

 

Flexplate not flywheel

 

Hmm... check your starter, could be sloppy and the gear could be moving back n forth just enough to hit the flywheel. Happened on my buddies camaro

 

lol... right... I was actually always picky about people calling it a flywheel IDK why I started calling it a flywheel


seems like the starter has nothing to really do with it, since the noise went away after I replace the flexplate the first time. I'm wondering if I need to buy a really hardcore flexplate since the 4l60e probably isn't use to having to move around 35x12.50 inch tires...

 

Did you find cracks on the first flexplate you replaced? Check the dowel pin area on the trans and see if they are loose or worn on the pins. The trans being off true center may put stress on the flexplate. Converters are heavy. During hard launches, the weight of the converter will not let the conv. move when the rest of the car moves-the "flexplate" will absorbe the delay, so to speak. Like when plow trucks slam into the piles of snow. The abrupt hit causes the torque conv. to keep moving forward and "spring" back to the float position. If this happens enough times, the flexplate will crack. Yours may be happening in the oposite direction. Usually, a HD flexplate cures this problem.

Hope this helps.