somtimes when for example i pull out of my driveway i go from reverse to drive and give it just a little throttle the truck like shudders and jerks but if i give it more throttle then its fine what is this? it usually only happens when its cold but it has happend once when it was warmed up so whats up with this? i do run a diablo sport predator and i usually always run it in the performance economy tune could this be tearing up my tranny already? ive had it on for around 6000 miles and i installed it at 69000 miles and i only put it in the extreme mode a few times just to show off to the ford and chevy fans you all know how that goes. thanks for any info!  

I have pertty much the same truck and somethimes it feels like you described. I also am running an edge stacked with a smarty. And yes its my tranny. It cant even hold the edge on#6 just slips. Lol u still have warrenty. Run her till she blows then take ur chip of n send her in.  

My truck (manual trans) used to shudder when pulling away from a stop. Turns out it was a frozen u-joint in the rear drive shaft. If you have 70,000 miles on it and haven't changed a u-joint, I'd bet that's what it is. I have 83,000 on my truck and have changed nearly EVERY u-joint on it. They just dry-up and seize.