My truck chatters upon launch at almost any rpm idle or not. I think it has a aftermarket clutch in it, is there anything else that you guys can think of that would cause this? I've been under the truck looking for loose items but cannot seem to find anything that is loose (driveline, rearend shackles etc.)Thanks.If you really really really hit the clutch just right at a idle you can get it to drive without chattering but thats it.. Its really annoying when pulling a big trailer.

Hot spots in the flywheel / Pressure plate? Oil or Fuel contaminated friction plate? (Typically got issues with slippage)

I have not nor do I want to pull the tranny to see if anything is wrong, could this be fairly normal with a stronger aftermarket clutch?

Well... I know mine is caused from fuel contamination... I had #6 injection line dribble down on the clutch and cause to slip now and then which in turn cause a hot spot... Which was shortly after I installed the clutch so my now is jerky or grab at launch now... I've gotten use to it... Same since I'm not going to pull the trans down to re-surface the flywheel and pressure plate to fix it...