Before you rebuild your 4L60E Transmission you will need a rebuild kit. Most higher end rebuild kits will include a new shift kit as well. An automatic transmission shift kit is only needed if you want the gears to shift sooner, but it can also reduce transmission wear by reducing or eliminating shift overlap
GM 4L60E Transmission Rebuild Teardown Working thru the valve body webbing, Rick goes over a proper tear down of the valve body, including the forward accumulator and solenoids. This is key to preparing for the repair or adding a shift kit to your 4L60E Transmission.
