Differential oil lubricates the gears, bearings, and other internal components of the rear axle, helping prevent overheating, wear, and premature failure.
Capacities vary depending on the truck model, axle configuration (single or tandem), and axle manufacturer (Meritor, Eaton, Dana, or Detroit).
Freightliner Differential Oil Capacity
| Model / Variant | Rear Axle Type | Typical Differential Oil Capacity | Approximate Liters |
|---|---|---|---|
| Cascadia Classic | Tandem Rear Axle (Meritor RT‑40/RT‑46) | 37–44 quarts | 35–42 L |
| New Cascadia (Detroit NFD) | Tandem Final Drives (Detroit Model 4/6) | 9–14 L axle oil + hub oils ~1.8 L each | 9–14 L + hubs |
| Columbia | Single Rear Axle (Dana) | 18–20 quarts | 17–19 L |
| Coronado | Tandem Rear Axle (Eaton / Meritor) | 38–42 quarts | 36–40 L |
| M2 106 / Business Class M2 | Single Rear Axle (Meritor / Dana) | 20–24 quarts | 19–23 L |
| 122SD | Tandem Rear Axle (Meritor RT‑46) | 40–44 quarts | 38–42 L |
| Classic XL | Tandem Rear Axle (Eaton DS404) | 38–41 quarts | 36–39 L |
| FLD120 / FLD132 | Tandem Rear Axle (Meritor) | 37–40 quarts | 35–38 L |
| Century Class | Tandem Rear Axle (Dana / Meritor) | 36–40 quarts | 34–38 L |
| 108SD / 114SD | Single or Tandem Axle Options | 18–44 quarts | 17–42 L |
| Argosy | Tandem Rear Axle (Meritor) | 40–44 quarts | 38–42 L |
| MT45 / Step Van | Single Rear Axle (Various) | 16–20 quarts | 15–19 L |
| Freightliner Bus (Rear Axle) | Single Rear Axle (Various) | 18–22 quarts | 17–21 L |
| Vocational / Specialty Freightliners | Varies by Configuration | 36–44 quarts | 34–42 L |
Related Semi Truck Differential Oil Capacity Chart(For All Models)
Key Notes
- Single rear axles typically require 18–24 quarts, while tandem rear axles require 36–44 quarts, depending on axle type and configuration.
- Modern Detroit axles have separate oil compartments for the axle housing and hubs, so total capacity may be listed as hub oil plus axle oil.
- Oil selection should follow manufacturer recommendations, commonly SAE 75W‑90 synthetic gear oil, 75W‑140 for severe duty, or 80W‑90 for older axles.
- Using the correct oil volume and type ensures proper lubrication, reduces wear, and can extend maintenance intervals.
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Differential Maintenance Tips
- Check Oil Level: Park the truck on a level surface, remove the fill plug, and ensure oil reaches the bottom of the fill hole.
- Change Interval: Standard interval is typically 250,000 miles, with synthetic oils allowing up to 500,000 miles in some axles.
- Signs of Low Oil: Unusual whining or grinding noises, overheating axle housing, metal particles in oil, and reduced fuel efficiency.
- Always Verify: Double-check your truck’s axle tag or service manual to confirm the proper capacity and recommended oil type.
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FAQs
What kind of oil does a Freightliner M2 differential take?
Freightliner M2 trucks typically use GL‑5 gear oil, with SAE 75W‑90 synthetic being the most common choice. For severe duty or higher temperature applications, 75W‑140 can be used.
Older models may use 80W‑90 conventional gear oil. Always follow the manufacturer’s specifications for your exact axle model.
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How to check axle oil level on a Freightliner?
- Park the truck on a level surface.
- Locate the axle fill plug on the rear differential housing.
- Remove the plug and check that the oil is level with the bottom of the fill hole.
- If the oil is low, top it up with the correct type of gear oil.
Can you overfill differential oil?
Yes, overfilling can cause issues. Excess oil can aerate when the differential heats up, leading to foaming, poor lubrication, and possible seal leaks. Always fill to the bottom of the fill hole and avoid exceeding the recommended capacity.
Is there a big difference between 75W‑90 and 80W‑90?
Yes. 75W‑90 is a fully synthetic gear oil with better cold-start flow and higher temperature stability, while 80W‑90 is typically mineral-based with thicker cold-flow characteristics. 75W‑90 is preferred for modern axles due to extended service intervals and improved efficiency.
How much oil does a Freightliner M2 take?
For a single rear axle, a Freightliner M2 usually requires 20–24 quarts (19–23 liters), depending on the axle model and manufacturer. Always confirm the exact volume from the axle tag or service manual.
How to check differential oil level?
- Ensure the truck is on a level surface.
- Remove the differential fill plug.
- Oil should be level with the bottom of the fill opening.
- If low, add the specified gear oil until it reaches the proper level.
- Replace the fill plug securely.
Final words
Freightliner differential oil capacity varies widely based on model, axle type, and configuration. Single axles hold roughly 18–24 quarts, while tandem axles range from 36–44 quarts.
Proper lubrication is critical for reducing gear wear, preventing overheating, and maintaining drivetrain performance. Always use the recommended oil type and confirm the exact capacity for your truck model to ensure reliable operation.
