Where are the shift sensors located on a 92 Chevy 4x4

Shift sensors are indicators for a computer controlled circuit. Most times, they are contained or housed within a solenoid pack. As they are an electronic monitor, the area they are housed in will usually have a multi-pin wiring harness leading to it. The harness connector is normally protected with a rubber grommet around it. I have seen these grommets "folded over/pinched" during assembly line installation. The purpose of the grommet is to form a water proof barrier within the harness connection. As this is a 4x4, it most likely sees somewhat rougher conditions and exposure. Any ammount of water spraythat reaches a weakened grommet is likely to penetrate through to the alloy electrical terminals. These "pins" rarely rust, but they DO corrode. The fine, powdery, blue corrosion inside the connections can act like an insulator and corrupt the signal. If disconnecting the harness pigtail is possible, physically look into the harness ends and at the pins. If there IS corrosion, try tapping the harness end against the transmission or transfercase to dislodge any loose particles. Usually, just a quick burst of air is enough to clear out the connection on the vehicle. Sometimes, that's all it takes. If there IS corrosion evident, FILL the cavity containing the pins with a dielectric gel/grease, before reinstalling the pigtail. DO NOT use silicone!