My mate and I installed a B&M shift in my car VT V6 Commodore. Box is a 4l60E. 1-2 under moderate throttle shifts nice and firm except at WOT it doesn't rev out, it shifts at 4000rpm and its a bit sluggish. Tried holding it in 1st and still shifts at 4k. 2-3 shifts at 5500 but not a firm shift. ...