2023 Freightliner M2 106 — Complete Fluid Type Specifications

Quick reference

Fluid	Type/Spec	Capacity
Engine oil (diesel)	API CK-4; SAE 10W-30 or 15W-40. Cummins CES 20086 (B6.7) or Detroit DFS 93K222 (DD5/DD8). Do NOT use FA-4 unless engine specifically approves.	Engine-dependent: ~15–20 qt (Cummins B6.7); ~17–30 qt (Detroit DD5/DD8). Verify on engine tag/OEM info.
Engine coolant	Extended-life OAT, nitrite-free. Meets ASTM D6210 and TMC RP 329/330; Cummins CES 14603 or Detroit Power Cool Plus OAT equivalent (red/pink).	Chassis/engine/heater dependent: ~5–10+ gal total. Verify by VIN/build sheet.
Transmission fluid (Allison automatic)	Allison-approved TES 668 or TES 295 (e.g., TranSynd). Dexron VI may be allowed but not for extended drains—follow Allison approvals list.	By series/sump: 1000/2000 ≈ 10–17 qt; 3000 ≈ 26–39 qt. Verify on trans ID tag.
Transfer case (if 4x4)	Varies by case. Commonly ATF (DEXRON III/MERCON) or SAE 75W-90 API GL-5. Follow transfer case tag/OEM spec.	~2–4 qt typical. Verify.
Front differential (if 4x4)	SAE 75W-90 (or 80W-140 for severe duty) API GL-5 full-synthetic. Meritor O-76N or Dana SHAES-256 Rev C.	~2–4 qt typical. Verify by axle model.
Rear differential(s)	SAE 75W-90 (or 80W-140 severe) API GL-5 full-synthetic. Meritor O-76N or Dana SHAES-256 Rev C.	Single: ~3–8 qt; tandem: per axle ~3–8 qt. Verify by axle model.
Brake system	Most M2 106 use air brakes (no DOT fluid). If hydraulic brakes: FMVSS 116 DOT 3 or DOT 4 per reservoir cap.	Hydraulic systems: reservoir ~1–2 qt total. Air brakes: N/A.
Power steering	ATF meeting DEXRON III/MERCON or heavy-duty PS fluid approved by the steering gear/chassis maker.	~2–4 qt typical. Verify by chassis option.
Washer fluid	Any automotive windshield washer fluid appropriate to climate (premix to freeze point).	~1–2 gal typical.
Diesel Exhaust Fluid (DEF)	ISO 22241 AUS 32 (32.5% urea).	Tank size varies by build: ~6–23 gal typical. Verify placard.

Engine oil

Powertrains in the 2023 Freightliner M2 106 are engine-optioned (commonly Cummins B6.7, some Detroit DD5/DD8). Use heavy-duty diesel oil that meets API CK-4. If equipped with a Cummins B6.7, select oil complying with Cummins CES 20086. If equipped with a Detroit DD5/DD8, use oil approved to Detroit DFS 93K222. SAE 10W-30 CK-4 is widely accepted for fuel economy; 15W-40 CK-4 is typical for high ambient/severe service. Do not use FA-4 oils unless your specific engine documentation permits it.

Capacity varies by engine and sump: roughly 15–20 quarts on most B6.7 variants and roughly 17–30 quarts on DD5/DD8, but confirm on the engine data tag or OEM service info for your exact build.

Intervals are duty-cycle dependent. Follow the engine maker’s oil drain recommendations (time/miles/hours) and consider oil analysis for severe service (PTO, high idle, stop‑and‑go). Replace the oil filter at every oil change.

Common pitfalls:

• Mixing CK-4 with obsolete specs or FA-4 without approval.
• Overfilling after a filter change—always check the dipstick after initial fill and a short run.

Engine coolant

Use an extended-life OAT (Organic Acid Technology), nitrite-free heavy‑duty coolant. Acceptable coolants meet ASTM D6210 and TMC RP 329/330. Engines commonly specify Cummins CES 14603 or a Detroit Power Cool Plus OAT–equivalent nitrite‑free ELC (typically red/pink). Never mix OAT with conventional green IAT or HOAT; if you must top off, use the same chemistry and color.

System capacity depends on radiator size, heater circuits, and engine: expect about 5–10+ gallons total. Fill with 50/50 premix using deionized or distilled water (60/40 in extreme cold only if allowed). Purge air thoroughly and pressure‑test caps.

Service notes:

• Many OAT ELCs are 5‑year/300,000‑mile service life; follow the coolant brand/OEM schedule.
• Do not add supplemental coolant additives (SCAs) to nitrite‑free OAT unless directed by the OEM.

Transmission fluid (Allison)

Most M2 106 trucks use Allison automatics (1000/2000/3000 series). Use only Allison‑approved fluids:

• TES 668 (latest) or TES 295 (e.g., TranSynd) for best durability and extended drain.
• Dexron VI may be permitted in some 1000/2000 units but does not provide extended drain intervals. Always verify on Allison’s approved list and your transmission ID tag.

Capacities vary: about 10–17 quarts for 1000/2000; about 26–39 quarts for 3000 (depending on pan/deep sump and cooler configuration). Follow the Allison fluid life monitor and service schedules; severe duty (PTO, frequent stops, high temps) shortens intervals. Do not use “universal” ATF or non‑approved fluids.

Transfer case (if 4x4)

A 4x4 M2 106 is uncommon and uses vendor‑supplied transfer cases (e.g., Marmon‑Herrington/Spicer). Fluids range from ATF (DEXRON III/MERCON) to SAE 75W‑90 API GL‑5 gear oil depending on the case. Capacity is typically 2–4 quarts. Always follow the transfer case tag and OEM literature. Change intervals are usually 30k–60k miles in severe duty.

Differentials

Axles are typically Meritor or Dana/Spicer. Use full‑synthetic API GL‑5 gear oil:

• SAE 75W‑90 for general service; 80W‑140 for heavy towing, high ambient, or severe duty.
• Meritor: spec O‑76N approved synthetic gear lubricants.
• Dana/Spicer: spec SHAES‑256 (Rev C or later).

Capacities vary widely by axle model: roughly 2–4 quarts for a driven front axle (on 4x4), and roughly 3–8 quarts per rear drive axle. Verify by axle tag (model and ratio).

Notes and pitfalls:

• Most heavy axles do not require limited‑slip friction modifier. If equipped with clutch‑type LSD, follow axle maker’s additive guidance; lockers/NoSPIN typically require none.
• After water fording or contamination, change gear oil immediately.
• Typical drain intervals range from 100k to 250k miles depending on duty; confirm with the axle OEM.

Brake system

Many M2 106 trucks use full air brakes—there is no hydraulic brake fluid reservoir. Maintain the air dryer and compressor per OEM schedule.

If your truck has hydraulic brakes, use FMVSS 116 DOT 3 or DOT 4 as printed on the master cylinder cap. Do not use DOT 5 silicone. Flush intervals are commonly every 2 years, but follow the brake system OEM guidance. Total fluid volume is small (about 1–2 quarts across the system).

Power steering

Freightliner commonly specifies ATF meeting DEXRON III/MERCON for the power steering/hydraulic assist system, or a heavy‑duty power steering fluid approved by the steering gear/chassis manufacturer. Capacity is about 2–4 quarts depending on hose/gear/reservoir size. Bleed air after service and avoid mixing different ATF types. Inspect hoses for seepage—aerated fluid will foam and cause assist noise.

Washer fluid

Use commercial windshield washer fluid premixed to a freeze point suitable for your climate. Capacity is typically 1–2 gallons. Do not use plain water in freezing conditions; methanol blends can evaporate—top off seasonally.

Diesel Exhaust Fluid (DEF)

Use only ISO 22241‑compliant DEF (AUS 32, 32.5% urea). Tank sizes vary widely by M2 106 build (roughly 6–23 gallons). Keep DEF clean—contamination or using non‑approved containers can damage the SCR system. Store DEF below 86°F (30°C); typical shelf life is 12 months. DEF can freeze; the system self‑thaws—do not add additives.

Final notes

Because the M2 106 is highly configurable, capacities and some approvals depend on the exact engine, transmission, axle, and cooling/heater options. Always verify each spec and capacity against the under‑hood labels, component ID tags (engine/trans/axle), the owner’s manual, and OEM service information.

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