Adapt-A-Case has a new tool that changes the way to align the pump on almost every transmission (excludes 6L80). Many different tools exist but they all seem to come up short somewhere. Our new T-7867AC aligns pumps from 7 inch diameter up to 10.5 inch diameter (plenty big for those 4R100's). There is nothing to twist by hand or with pliers . Simply put in place and squeeze the handles.