1997-2001 the NSS wiring harness connector is different but the internals are the same - mostly.The TCU can't tell, this can lead to some common transmission shifting symptoms. No connections indicates that the shifter is in OD - OR that the NSS is dirty. The ISS and OSS for these years are the same part number one may be substituted for the other for spare parts purposes. A 16 pulse/rev Input Speed Sensor was also added. The Output Speed Sensor changed from a 1pps reed switch to a 4 pulse/rev variable reluctance pickup similar to the RENIX CPS and most ABS wheel speed sensors. 1998-01, the AW4 changed electrically, but is otherwise the same as 1990.5-1997 units.A simple cut and splice will solve this problem. 1997, the AW4 is exactly the same as the 1990.5-1996 units, except the electrical connector for the wiring harness changed.It was no longer available behind the 2.5L engine. 1990.5-1996, the AW4 switched to a 23 spline output shaft and a 0.75:1 OD ratio.4.0L and 2.5L transmissions are fundamentally the same, except for the torque converter and bellhousing, which are unique for each motor. 1987-1990, the AW4 had a 21 spline output shaft, a 1 pulse per revolution reed switch Output Speed Sensor, no Input Speed Sensor, and a 0.705:1 OD ratio.Year splits, aka 'will this transmission fit my XJ?' It should only be powered in 3rd or Overdrive gear.Īll solenoids should show 11 to 15 ohms when the transmission has reached running temperature. Solenoid 3 locks the torque converter clutch (direct drive) when powered. Overdrive - solenoid 1 OFF, solenoid 2 OFF If the electronics are disconnected, this will put the transmission in 1st.Ģnd gear is not available without some sort of electronics (stock, a toggle switch in the dash, whatever) powering the solenoids. The transmission hydraulics enable engine braking in 1st gear with the gearshift in this position. If the electronics are disconnected, this will put the transmission in 3rd.ġ-2 - in this gearshift position, gears 1 and 2 are available via electronic control. If the electronics are disconnected, this will put the transmission in overdrive.ģ - in this gearshift position, 1, 2, or 3 may be electronically selected. See the table after this section for details. Shift firmness is controlled by a throttle valve cable which meters fluid pressure into the valve body based on throttle position.ĭrive - in this gearshift position, 1, 2, 3, or Overdrive may be electronically selected. Gear selection is part hydraulic and part electronically controlled via solenoid valves. It has 3 regular forward gears and 1 overdrive gear, along with a torque converter containing a lockup clutch. It was also rarely used in 2.5L equipped XJs with the automatic transmission option, 1987-1990*.

The AW4 transmission was used in 4.0L equipped XJs from 1987 through 2001.

Np231 speed sensor installation