A Ford Expedition Owner's Guide to the Transmission Output Speed Sensor (2003-2007)
If your 2003-2007 Expedition is shifting hard or the O/D light is flashing, the transmission output speed sensor is a likely culprit.
- A bad output speed sensor is a very common cause of harsh shifting, a flashing O/D light, and speedometer issues on 2003-2007 Expeditions.
- Look for diagnostic trouble codes P0720 and P0722, which point directly to a fault with this sensor.
- Replacement is an easy DIY job for most owners, requiring basic tools and access to the side of the transmission.
- While Motorcraft is the OEM choice, brands like NGK/NTK offer a high-quality, reliable aftermarket alternative for a lower price.
Is Your Expedition Shifting Erratically?
A faulty Automatic Transmission Output Shaft Speed Sensor (OSS) is a common problem on the 2003-2007 Ford Expedition. This sensor is essential for smooth transmission operation, and when it fails, the symptoms are hard to ignore. Because it's a relatively simple and inexpensive part to replace, it's often one of the first things to check when you experience transmission-related issues.
Symptoms of a Failing Output Speed Sensor
When the OSS sensor begins to fail, your truck's computer gets bad information, leading to several noticeable problems:
- Harsh or Delayed Shifting: The transmission may slam into gear, or hesitate before shifting.
- Flashing "O/D OFF" Light: The overdrive off light on your gear selector may start blinking. This is a classic sign of a transmission fault code being stored.
- Inaccurate Speedometer: The speedometer might behave erratically, jump around, or stop working altogether.
- Check Engine Light: A failing sensor will trigger the check engine light. Common trouble codes include P0720 (OSS Circuit Malfunction) and P0722 (OSS No Signal). 🎬 Watch: Understanding P0720 causes and how to fix them
- Limp Mode: In some cases, the vehicle may enter a 'limp mode' with severely limited power to prevent further damage.
Choosing the Right Aftermarket Sensor
For electronic parts on Ford trucks, many mechanics recommend sticking with the original manufacturer. However, high-quality aftermarket brands can provide reliable performance at a better price point.
- Motorcraft: This is Ford's own brand and the Original Equipment (OEM) part. It guarantees perfect fitment and electronic compatibility. While it's the most expensive option, it's the benchmark for quality and reliability. 🎬 See this quick tip for fixing harsh shifting issues
- NGK (NTK): NTK is the sensor division of NGK. They are a massive OEM supplier for many car manufacturers and have a reputation for producing high-quality electronic components that often meet or exceed OEM specs. Many consider NTK a top-tier aftermarket choice that is a smart alternative to Motorcraft.
- Standard Ignition (SMP): Standard is a long-standing aftermarket company that produces a huge range of parts. They are generally considered a solid, reliable mid-tier option for budget-conscious repairs.
Typical Replacement Costs
The cost to replace the output speed sensor is reasonable, especially if you do it yourself. The part is easily accessible on the outside of the transmission.
| Part or Service | Estimated Cost |
|---|---|
| New OEM (Motorcraft) Part | $115 - $140 |
| New Aftermarket Part | $33 - $80 |
| Shop Labor | $95 - $150 |
| Total Professional Replacement | $130 - $290 |
Frequently Asked Questions
Where is the output speed sensor on a 2003-2007 Expedition?
It is located on the exterior of the transmission housing, toward the rear of the vehicle. On 2WD models, it's on the main transmission case, often on the driver's side. On 4WD models, it is located on the transfer case. It is held in place by a single bolt.
What's the difference between the input (TSS) and output (OSS) speed sensor?
Your Expedition has two main speed sensors. The Turbine Shaft Speed (TSS) or input sensor measures the speed of the transmission's input shaft from the engine. The Output Shaft Speed (OSS) sensor measures the speed of the shaft going out to the wheels. The computer compares both signals to determine the correct gear ratio and to detect slipping.
Are there any recalls for this sensor?
No, there are no specific recalls from Ford or NHTSA for the automatic transmission output speed sensor on the 2003-2007 Expedition. However, this generation of Expedition is known for a variety of transmission problems, and a failing sensor is a common and relatively minor issue to fix.
Do I need to reset the computer after replacing the sensor?
It is a good practice to clear the trouble codes with a scan tool after the repair. You can also disconnect the battery for about 15 minutes to reset the computer. After replacement, the computer will need to go through a short relearning process as you drive.
Helpful Videos
Technical Specifications
OEM Part Numbers: 6L3Z-7H103-AA DY1215 F85Z-9E731-AB DY1123
This is a 2-pin sensor typically held in place by a single 8mm or 10mm bolt. Note: Part numbers may differ between early (2003) and later (2004-2007) models in this range. Always verify the correct part for your specific vehicle year and transmission before ordering.
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
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