I have the Auto crapper, while pulling the boat it has started really jumping and shuddering under load if I let off the go pedal it stops, if I ease back onto the throttle it normally wont do it. I also noticed if I turned up the juice to 4 and get on it, it will do the same thing without a trailer? Torque converter?

 

No enough info to really help you.
Is it doing this in 3rd or OD? Can you tell if it is the converter clutch unlocking?
Do a search on converter unlocking or maybe shudder, and even electrical noise.

 

its not hunting between lockup if that's what your thinking, it shakes the whole truck pretty hard, as far as noise all I hear is the stuff in the cab rattling and jumping around. It seems like its between third and forth.

 

Sounds like you have had all the fun a stock tranny can deliver behind a modded engine. Remember more horsepower equals less reliability.

 

probably true.