Hello, I have a 95 1500 Suburban with 4L60 tranny. It seems to be having some issues where when I put it in OD to drive normal pace, it quickly shifts into the highest gear right after the initial pick up. When I try and press the gas pedal to the floor, the tranny still will not shift to the next lower gear so the truck can have a better pick up speed. I have already replaced the filter and trans fluid few months ago and I may have over fill it, not 100% sure. Could this be the case that's causing it? Does anyone here may have experienced this issue before? Your help will be greatly appreciated.