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2018 Silverado 1500 Transmission Fluid Change Interval & Rough Shifting

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Amanda S. · rep 0 · May 22, 2:38 AM · 1 replies · solved · Question

Vehicle: 2018 Chevrolet Silverado 1500 LT

Hey everyone,

I've got a 2018 Chevrolet Silverado 1500 LT with the 5.3L V8 and about 85,000 miles on it. I've been noticing some slightly rougher shifts lately, especially when it's cold, and I'm wondering if it's time to change the transmission fluid. The owner's manual is a bit vague, talking about 'lifetime fluid' but also mentioning severe duty intervals.

I tow a boat occasionally during the summer, maybe 5-6 times a year, and do a fair bit of highway driving. Is 85k miles too long for the original fluid? What's the recommended interval for a truck like mine, and is this something a DIYer can tackle or should I take it to a shop? Any advice on fluid types or specific procedures would be great!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 2:38 AM

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ClearTheCode admin answer:

It's a common question regarding GM's 'lifetime' transmission fluid, especially for trucks like your 2018 Silverado 1500 LT. While GM suggests the fluid can last the vehicle's life under normal conditions, towing and higher mileage often warrant earlier service.

  1. Recommended Interval: For vehicles that tow or operate under severe conditions (which occasional towing qualifies for), a transmission fluid and filter change is generally recommended between 60,000 and 100,000 miles. Given your 85,000 miles and occasional towing, it's a good time to consider this service.
  2. Symptoms & Causes: Rough shifting, especially when cold, can be an indicator of degraded transmission fluid, which loses its lubricating and cooling properties over time. It can also be caused by internal transmission issues, but starting with fluid maintenance is a good diagnostic step.
  3. DIY vs. Professional: Changing transmission fluid on a modern Silverado can be a DIY task if you're comfortable with vehicle maintenance. It typically involves dropping the pan, replacing the filter, and refilling with the correct fluid. However, a full fluid flush (which replaces nearly all the fluid) is usually best left to a professional shop with specialized equipment. Ensure you use Dexron VI fluid, as specified for your transmission.
  4. Checking Fluid Level: Always check the transmission fluid level with the engine running and at operating temperature, following the specific procedure in your owner's manual (often involves cycling through gears).
  5. When to See a Shop:
    • If the rough shifting persists or worsens after a fluid and filter change.
    • If you notice any warning lights, such as a 'Service Transmission' message or a Check Engine Light. A common OBD-II code for transmission issues is P0700 (Transmission Control System Malfunction), which indicates the Transmission Control Module (TCM) has detected a fault. This code usually requires further diagnosis to pinpoint the specific transmission issue.
    • If you're unsure about the procedure or don't have the right tools, a professional can ensure the job is done correctly and safely.
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