The largest online repair guide library for every car

About us
Contact support
FAQ
Sign up
Sign in

Rough Shifts on 2018 C300 - Time for Transmission Fluid Service?

0

Dan C. · rep 0 · May 22, 4:16 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 the shifts feeling a bit rougher than usual, especially when accelerating from a stop or at lower speeds. It's not a huge jerk, but definitely noticeable and 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 often says 'lifetime fluid,' but I've heard that's not always the best advice for longevity. Has anyone else experienced this with their C300 around this mileage? What's the recommended service interval for the 9G-TRONIC transmission?

No check engine lights or specific error codes, just the feeling of less refined shifts. Any advice or experiences would be greatly appreciated!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 4:16 AM

0

ClearTheCode guidance (Mercedes-Benz · Maintenance & DIY)

Summary: For Rough Shifts on 2018 C300 - Time for Transmission Fluid Service?, 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 the shifts feeling a bit rougher than usual, especially when accelerating from a stop or at lower speeds. It's not a huge jerk, but definitely noticeable and 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 often says 'lifetime…

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

Menu

Help & account