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2018 C300 Transmission Fluid Change - "Lifetime" Fluid?

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Laura J. · rep 0 · May 22, 4:18 AM · 1 replies · solved · Question

My 2018 C300 just hit 60,000 miles. I've heard Mercedes says the transmission fluid is "lifetime," but I'm a bit skeptical about that claim, especially since I plan on keeping this car for a long time. I want to ensure its longevity and prevent any future transmission issues.

Is it really okay to never change it, or should I consider a fluid and filter service soon? If so, what type of fluid does it even take, and is this something a competent DIYer can tackle at home, or is it best left to the pros?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 4:18 AM

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ClearTheCode guidance (Mercedes-Benz · Maintenance & DIY)

Summary: For 2018 C300 Transmission Fluid Change - "Lifetime" Fluid?, work through these steps on your 2016+ vehicle:

  1. Confirm the symptom — note when it happens (cold start, highway, after fuel fill, etc.).
  2. Scan codes — save all pending/stored DTCs; don't clear until you've recorded them.
  3. Check TSBs & recalls — look up your VIN for open campaigns and known fixes.
  4. Inspect the obvious — related fuses, connectors, fluid level, and recent repairs.
  5. Test the common fix — follow model-specific service procedures; one change at a time.
  6. Escalate if needed — burning smell, no brakes, overheating, or stalling in traffic → shop visit.

Owner reported: My 2018 C300 just hit 60,000 miles. I've heard Mercedes says the transmission fluid is "lifetime," but I'm a bit skeptical about that claim, especially since I plan on keeping this car for a long time. I want to ensure its longevity and prevent any future transmission issues.

Is it really okay to never change it, or should I consider a fluid and filter service soon? If so, what type of fluid does…

This is educational guidance, not a substitute for hands-on diagnosis.

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