1. Safety First:
* Parking Brake: Engage the parking brake firmly. This is crucial.
* Wheel Chocks: Use wheel chocks to further secure the truck.
* Jack Stands: Never work under a vehicle supported only by a jack. Use jack stands rated for the vehicle's weight.
* Gloves and Eye Protection: Protect yourself from grease, dirt, and potential injury.
2. Diagnosing the Problem:
Before replacing the cable, confirm it's the actual culprit. The fact you've manually shifted the transmission suggests the cable might *not* be the sole problem. You'll need to investigate:
* Shift Linkage: Inspect the linkage connecting the shifter inside the cab to the cable. Look for bent, broken, or loose components. There might be an adjustment needed or a broken part that prevents proper engagement.
* Cable Condition: Examine the existing shift cable for fraying, kinks, or broken sections along its entire length, including inside the transmission case and at both ends. A visual inspection might not catch all problems.
* Transmission Issues: If the linkage and cable seem okay, the problem likely lies within the transmission itself. Manual shifting suggests potential internal damage (worn parts or broken components). This is a much more serious and expensive issue.
3. Replacing the Shift Cable (if determined to be faulty):
This is generally a moderately difficult job, requiring some mechanical aptitude.
* Disconnect the Battery: This prevents accidental short circuits.
* Access the Cable: This usually involves removing parts of the console or access panels. Consult a repair manual specific to your 1996 Ford Ranger 4.0L for the exact steps. The manual will show where the cable attaches to the transmission and the shifter lever.
* Remove the Old Cable: Carefully disconnect the cable from both the transmission and the shifter. Take pictures and notes to aid reassembly. You'll likely need special tools to remove and install the cable retaining clips.
* Install the New Cable: Route the new cable following the path of the old one. Pay close attention to proper alignment and routing – this is crucial for correct shifting operation. Use the pictures and notes from earlier.
* Reconnect the Cable: Carefully attach the cable to both the transmission and the shifter. Ensure secure connections.
* Test the Shifter: After reconnecting the battery, try shifting through all gears. If the problem persists, the issue is likely *not* the cable.
4. Repair Manual:
A repair manual specific to your 1996 Ford Ranger 4.0L is absolutely essential. It will provide detailed diagrams, torque specifications, and step-by-step instructions. You can find these manuals online or at auto parts stores. This is the best investment to help you succeed.
Important Considerations:
* Internal Transmission Damage: If replacing the cable doesn't solve the problem, the transmission itself may require professional repair or replacement. This is a significant expense.
* Professional Help: If you're not comfortable working on your vehicle, seek the assistance of a qualified mechanic. Improper repair can worsen the problem or cause further damage.
Before you even consider replacing the cable, thoroughly investigate the linkage and the transmission's internal condition. A proper diagnosis is critical to avoiding unnecessary expense and wasted effort.
