Replacing the park/neutral position (PNP) switch for a 4l80-e/4l85-e automatic transmission starts by using the park brake then setting the transmission to neutral. Drivers should remove the front propeller shaft when their vehicle features 4-wheel drive (4WD). The first step is to support the vehicle properly before disconnecting the electrical connector of the pnp switch. Neutralize and raise the vehicle before removing the range selector lever ball stud end of the cable followed by the manual shaft nut and the control lever from the manual shaft. Next, remove the pnp switch bolts and take off the pnp switch from the manual shaft; the manual shaft requires filing its outer edges to remove excess burrs before the pnp switch will slide off successfully. To mount the pnp switch position it over manual shaft flat areas before pushing it onto the manual shaft until the switch bracket meets transmission mounting brackets. A new pnp switch provides its own positive assurance bracket so the park neutral switch aligner becomes unneeded. Position the pnp switch bolts finger tight first before placing the park neutral switch aligner (J 41364-A) on the switch with its slots matching the tool's lower tabs. Tighten the bolts to 25 nm (18 ft. Lbs.) after you align the upper locator pin with the slot on the top of the switch through the aligner rotation. The user should remove both components: the aligner together with the positive assurance bracket. Reinstall the control lever to the manual shaft with the nut, tightening it to 25 nm (18 ft. Lbs.)the installation process requires you to attach the range selector cable end to the range selector lever ball stud and then reconnect the pnp switch electrical connector. If the vehicle has 4wd, reinstall the front propeller shaft, lower the vehicle, and check the pnp switch for proper operation, ensuring the engine starts only in the park (P) or neutral (N) positions; replace the switch if it fails to operate properly.