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2018 C300 Transmission Service - Rough Shifts & Hesitation

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Tom H. · rep 0 · May 22, 4:19 AM · 1 replies · solved · Question

Hey everyone, I've got a 2018 Mercedes-Benz C300 with about 65,000 miles on it. Lately, I've noticed some slight hesitation and rougher shifts, especially when accelerating from a stop or at lower speeds. It's not terrible, but definitely not as smooth as it used to be.

I'm wondering if it's time for a transmission fluid and filter change. I know Mercedes has specific service intervals, but I've heard conflicting things about whether this is a 'lifetime' fluid or not.

Is this something I can tackle myself, or is it strictly a dealer job given the complexity of Mercedes transmissions? What are the recommended intervals for the 9G-TRONIC transmission? Any advice or experiences would be greatly appreciated!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 4:19 AM

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ClearTheCode guidance (Mercedes-Benz · Maintenance & DIY)

Summary: For 2018 C300 Transmission Service - Rough Shifts & Hesitation, 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: Hey everyone, I've got a 2018 Mercedes-Benz C300 with about 65,000 miles on it. Lately, I've noticed some slight hesitation and rougher shifts, especially when accelerating from a stop or at lower speeds. It's not terrible, but definitely not as smooth as it used to be.

I'm wondering if it's time for a transmission fluid and filter change. I know Mercedes has specific service intervals, but I've …

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

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