Freightliner Cascadia 126 · fluids
Fluids & Fill AmountsHow much oil, coolant, DEF and gear oil this truck takes, and what specification to buy.
Set the year first
Then read the How much column as a refill quantity, not a dry fill. Fill to the dipstick or sight glass and treat the number as a starting point — a drain never gets everything out.
Fill amounts for Freightliner Cascadia 126
| Fluid | How much | What to buy | Years | Source |
|---|---|---|---|---|
| Engine oil - DD15 Gen 5 (oil + filter)Change it: 35,000-75,000 mi depending on duty and oil analysis | 45 qt (43 L) | Detroit DFS 93K222 (CK-4) or 93K223 (FA-4) | 2021–2026 | Verified |
| Engine oil - DD15 EPA07/EPA10/GHG14 (oil + filter)Change it: Per oil analysis program | 45.4 qt (43.0 L) | Detroit DFS 93K222 (CK-4) | 2007–2016 | Verified |
| Engine oil - DD15 total dry volumeChange it: - | 51.8 qt (49.0 L) | As above | 2007–2026 | Verified |
| Engine oil - DD13 Gen 5 (oil + filter)Change it: Per oil analysis program | 40 qt (38 L) | Detroit DFS 93K222 / 93K223 | 2017–2026 | Verified |
| Engine coolantChange it: Test at PM | Not verified - consult OEM service manual | Detroit Genuine Coolant / OAT extended life | 2018–2026 | Unconfirmed |
| Diesel exhaust fluid (DEF) tankChange it: Fill at every fuel stop | 13 gal (49 L), 23 gal (87 L) or 53 gal (200 L) by tank option | ISO 22241 / API certified DEF | 2018–2026 | Verified |
| Fuel tankChange it: - | 60-205 gal (227-775 L) by tank option | Ultra-low-sulfur diesel, 15 ppm max | 2018–2026 | Verified |
| Transmission - Detroit DT12Change it: Not verified - consult OEM service manual | Not verified - consult OEM service manual | Detroit-approved synthetic ATF | 2018–2026 | Unconfirmed |
| Rear axle / differential (tandem)Change it: Not verified - consult OEM service manual | Not verified - consult OEM service manual | API GL-5 75W-90 or 75W-140 synthetic | 2018–2026 | Unconfirmed |
Sources: DD Engine Oil Capacities (DTNA); DD Engine Oil Capacities (DTNA), GHG14 table; DD Engine Oil Capacities (DTNA), GHG17 table; Detroit DD Platform Operators Manual Ch. 18; Detroit DD15 Gen 5 spec sheet DDC-EMC-FLY-0120; Freightliner Cascadia 126 specification sheet (Daimler Truck, 2024)
Two ways to wreck an engine in five minutes
Overfilling an oil pan aerates the oil and can damage bearings. Running a cooling system low can crack a liner or a head before the gauge even moves. Fill slowly, then check the dipstick or sight glass twice.