This kit uses a stock 2WD 4L60E output shaft with a 11” stickout that needs to be shortened. We then take our 51-0405 adapter housing and bolt it to the transmission. This adapter takes the hex bolt pattern on the 4L60E and converts it to a square bolt pattern to make the 4L60E look just like an earlier GM automatic. The stock main shaft should have a reluctor on the shaft which will line up with the sensor hole on our main adapter housing.
(The cut off length on the main shaft is measured with the 51-0405 installed.)