### Gearbox Oil Change on Massey Ferguson MF135/M148 Tractor

#### Tools Needed:
1. **Wrenches**: Adjustable or socket set
2. **Oil Drain Pan**: To catch old oil
3. **Funnel**: For pouring new oil
4. **Torque Wrench**: To ensure proper tightening of bolts
5. **Rags**: For cleaning
6. **Safety Goggles**: Eye protection
7. **Gloves**: Hand protection
8. **Oil Filter Wrench**: If changing the filter
9. **Replacement Oil**: Check specifications (usually 80W-90 gear oil)
10. **Replacement Gasket**: If necessary for the drain plug

#### Safety Precautions:
1. **Park on a Level Surface**: Ensure stability when working on the tractor.
2. **Engage the Parking Brake**: Prevents accidental movement.
3. **Use Proper PPE**: Wear gloves and goggles to protect against oil splashes.
4. **Let Engine Cool**: Avoid burns from hot engine components.

#### Step-by-Step Procedure:

1. **Prepare the Work Area**:
- Park the tractor on a flat, stable surface.
- Engage the parking brake and turn off the engine.
- Place the oil drain pan under the gearbox drain plug.

2. **Locate the Drain Plug**:
- Identify the gearbox drain plug, usually located at the bottom of the gearbox casing.

3. **Remove the Drain Plug**:
- Using the appropriate wrench, carefully loosen and remove the drain plug.
- Allow the old oil to fully drain into the oil pan. This can take several minutes.

4. **Inspect the Drain Plug**:
- Clean the drain plug and inspect for wear. Replace the gasket if necessary to prevent leaks.

5. **Replace the Drain Plug**:
- Once the oil is drained, re-install the drain plug and tighten it securely using a torque wrench (consult the manual for torque specifications).

6. **Remove the Fill Plug**:
- Locate the fill plug on the side of the gearbox. This is typically higher up than the drain plug.
- Use the wrench to loosen and remove the fill plug.

7. **Add New Gear Oil**:
- Using a funnel, pour the new oil into the gearbox through the fill hole. Fill until oil reaches the recommended level (check the manual for specifics).

8. **Replace the Fill Plug**:
- Reinstall the fill plug and tighten it securely.

9. **Check for Leaks**:
- Start the tractor and let it run for a few minutes. Check around the drain and fill plugs for any signs of leakage.

10. **Dispose of Old Oil**:
- Properly dispose of the old oil at a recycling center or as per local regulations.

#### Common Pitfalls to Avoid:
- **Overfilling**: Always check the oil level after adding; overfilling can cause foaming and damage.
- **Neglecting the Gasket**: Replace the drain plug gasket if it’s worn to avoid leaks.
- **Using Incorrect Oil**: Ensure that you are using the correct type and grade of oil as specified in the manual.
- **Not Cleaning the Drain Area**: Ensure that no debris falls into the gearbox during the oil change.

#### Replacement Parts:
- **Oil Filter**: If applicable and changing, ensure you have the correct filter.
- **Gaskets**: Always have replacement gaskets for drain and fill plugs if they show signs of wear.

By following these steps carefully, you can successfully change the gearbox oil on a Massey Ferguson MF135/M148 tractor, ensuring its smooth operation and longevity.
rteeqp73