Trans Help

[lariat06]

I have a 06 6.0 with stock auto trans. Mods are 4" exhaust, Tony Wildman extreme tune, wicked wheel II in stock turbo. Normal driving the truck shifts fine and has no issues. Every once in a while if i floor it and let it wind up a little bit. I then let off to let the truck slow its self down, when i go to get back in it at normal throttle it will just rev up and not move. It will do that a few times before going back into gear letting me keep moving. What could it be?

 

[sootie]

codes?

 

[lariat06]

not throwing any codes. and it only seems to do it if i floor it and it down shifts. if i easily roll into it and it stays in its current gear it does just fine.