i have boosted mine in 3rd several times running a dual disc 12cb iron, depending on how hard i have slipped it a couple of times, it was kinda weird, one time it would do it the next time it wouldnt, i maybe had a oil leak, i now have a triple disc, and 3rd gear launches are to dang easy. i even did a fourth but couldnt get it to hook up and was eating my tires up really fast.
8000 lb truck