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Rough Shifting & Hesitation in my 2018 CT6 3.6L - Transmission Issues?

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Mike T. · rep 0 · May 22, 3:58 AM · 1 replies · solved · Question

Hey everyone,

I've been experiencing some really frustrating issues with my 2018 Cadillac CT6 Premium Luxury, which has the 3.6L V6 engine and the 8-speed automatic transmission. Lately, the shifts have become very harsh, especially between 1st and 2nd gear, and sometimes 2nd and 3rd. It feels like a jolt.

Also, there's a noticeable hesitation when accelerating from a stop or when trying to downshift for passing. It's not consistent, but it's happening more frequently now. I'm worried this might be a serious transmission problem. Has anyone else with a similar model experienced this? What was the fix?

No check engine light yet, but the driving experience is definitely degraded. Any advice before I take it to the dealer?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 3:58 AM

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ClearTheCode guidance (Cadillac · Engine & drivetrain)

Summary: For Rough Shifting & Hesitation in my 2018 CT6 3.6L - Transmission Issues?, 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 been experiencing some really frustrating issues with my 2018 Cadillac CT6 Premium Luxury, which has the 3.6L V6 engine and the 8-speed automatic transmission. Lately, the shifts have become very harsh, especially between 1st and 2nd gear, and sometimes 2nd and 3rd. It feels like a jolt.

Also, there's a noticeable hesitation when accelerating from a stop or when trying to down…

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

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