Hi,
The two are likely connected. (Speedometer/shifting). That is where I would recommend starting. Here are directions for replacement. The attached picture correlates with the directions.
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1996 Mercury Sable V6-183 3.0L DOHC VIN S MFI
AX4N Automatic Transaxle
Vehicle Powertrain Management Sensors and Switches - Powertrain Management Sensors and Switches - Computers and Control Systems Vehicle Speed Sensor Service and Repair Procedures AX4N Automatic Transaxle
AX4N AUTOMATIC TRANSAXLE
pic 1
REMOVAL AND INSTALLATION
1. Disconnect battery ground cable and positive battery cable.
NOTE: When the battery has been disconnected and reconnected, some abnormal drive symptoms may occur while the Powertrain Control Module (PCM) relearns its adaptive strategy. The vehicle may need to be driven 16 km (10 miles) or more to relearn the strategy.
2. Raise and suitably support vehicle on hoist.
3. Remove three bolts, seven nuts and Y-pipe assembly from vehicle.
4. Disconnect vehicle speed sensor electrical connector.
5. Remove vehicle speed sensor retaining bolt and Vehicle Speed Sensor (VSS) from transaxle.
6. To install, reverse Removal procedure. Tighten VSS retaining bolt to 3.4-4.5 Nm (31-39 lb in). Tighten Y-pipe assembly nuts and bolts to 34-46 Nm (26-34 lb ft).
Image (Click to make bigger)
Friday, March 5th, 2021 AT 7:52 PM