To replace the park/neutral position switch of a 4l80-e/4l85-e transmission, first apply the park brake and put the gearshift in the neutral position. Lift the vehicle and remove the nut connecting the transmission control lever to the manual shaft and also remove the transmission control lever. However, pull the electrical connectors from the switch and remove the bolts holding park/neutral position switch to the transmission and then pullout the switch from the manual shaft. If the switch will not slide off with ease, file the outer edge of the manual shaft to ensure there are no burrs. In installing, line up the switch hub flats with the flats of the manual shaft and insert the switch on the manual shaft until the mounting bracket comes into contact with the bosses of mounting transmissions. As long as a new switch is being installed, it will have a positive assurance bracket as well, and therefore neutral position adjustment tool will not be required. Install the switch on to the transmission with only 2 bolts finger tight, and then with fitting the positions of the ingraining j 41364-a neutral position adjustment tool (J 41364-A) upon the switch; make certain that the given slot of the switch is placed so that it accepts alignment within the lower tabs of the tool. Swivel the tool for the upper locator pin to line up with the slot of the switch and then tighten the bolts that hold the switch in location to 25 nm (18 ft. Lbs.). Take off j 41364-a from the switch, and if it is applicable - take off the positive assurance bracket. Reconnect the electrical connectors to the switch and install the transmission control lever to the manual shaft using the nut and tightly fix it to 25 niger m (18 ft. Lbs.). Finally, lower the vehicle and check the switch for proper operations to ensure that the engine starts only when in p (Park) and n (Neutral). If it is not working properly, change out the switch.