The largest online repair guide library for every car

About us
Contact support
FAQ
Sign up
Sign in

2018 Sierra 1500 rough shifting - time for transmission fluid change?

0

Heather Y. · rep 0 · May 22, 3:45 AM · 1 replies · solved · Question

My 2018 GMC Sierra 1500 SLT, with about 85,000 miles, has started shifting a bit rough lately, especially between 2nd and 3rd gear. I've heard that GMC transmissions can be sensitive to fluid condition.

I'm wondering if it's time for a transmission fluid and filter change. The owner's manual suggests checking it, but doesn't give a super clear interval for replacement under normal conditions.

Has anyone with a similar Sierra experienced this? Is this a DIY job or something best left to a professional? What type of fluid should I use?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 3:45 AM

0

ClearTheCode guidance (Gmc · Maintenance & DIY)

Summary: For 2018 Sierra 1500 rough shifting - time for transmission fluid change?, 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 GMC Sierra 1500 SLT, with about 85,000 miles, has started shifting a bit rough lately, especially between 2nd and 3rd gear. I've heard that GMC transmissions can be sensitive to fluid condition.

I'm wondering if it's time for a transmission fluid and filter change. The owner's manual suggests checking it, but doesn't give a super clear interval for replacement under normal conditions.

Ha…

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

Menu

Help & account