The OE cast aluminum forward piston frequently breaks due to rough castings and high stresses. This billet aluminum forward piston eliminates these concerns by using high strength billet material and a design with added contours in the high stress areas. No machining or modification is required to use this piston and it can be used in all 4L60/4L60-E/4L65-E as long as it is used in conjunction with an aluminum over run piston.