Remove the cable from the negative terminal of the battery and proceed to the raising of the car on jackstands. The speed sensors of the automatic transmission are situated on the left-hand side of the transmission housing; the front sensor is the Turbine Shaft Speed (TSS) sensor, and the rear one is the Output Shaft Speed (OSS) sensor. Unplug the electrical connector to the TSS sensor by pulling on the tab and the unplugging it from the sensor, next, remove the bolt that secures the TSS sensor and the O-ring from it and replace the used O-ring with a new one. Installation is carried out in the reverse sequence making sure that the TSS sensor retaining bolt has been tightened as required. For the OSS sensor, take off the electrical connector and the retaining bolt, and also the old O-ring should be replaced with a new one, and then reverse the procedures of this section and tight the retaining bolt firmly. VSS is located on the left side Extension Housing for the 2 WD and to the left side transfer case Extension Housing for 4 WD. Pull out the electrical connector from the VSS, undo the mounting bolt and then remove the VSS sensor. Remove the old O-ring and replace it with a new one and replace the same sensor and tight down the mounting bolt as tightened before.