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2018 Silverado 8-Speed Transmission Shudder - Is this normal?

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Mark S. · rep 0 · May 22, 2:39 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 the 8-speed automatic transmission. Lately, I've been noticing a distinct shudder or vibration, especially when accelerating lightly between 20-50 mph, or during shifts. It feels like driving over rumble strips for a second or two.

I've heard about issues with these 8-speeds, sometimes called the 'Chevy shudder.' Is this a known problem, and what are the common fixes? I'm worried about long-term reliability and don't want to ignore it if it's a sign of something serious.

Any advice on what to tell the dealership or if there are any specific TSBs I should reference would be greatly appreciated. Thanks!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 2:39 AM

0

ClearTheCode admin answer:

The 'Chevy shudder' you're experiencing in your 2018 Chevrolet Silverado 1500 with the 8L90 8-speed transmission is a widely reported issue and is indeed a known concern. It's often attributed to a few primary causes:

  1. Torque Converter Clutch (TCC) Issues: The most common cause is premature wear or degradation of the transmission fluid, leading to friction material breakdown in the torque converter clutch. This causes inconsistent engagement and the shudder sensation.
  2. Transmission Fluid Degradation: The original transmission fluid (Dexron HP) in many of these units was found to be hydroscopic, meaning it absorbed moisture over time. This can lead to fluid breakdown and lubrication issues.

What to do:

  1. Check for TSBs: There are several Technical Service Bulletins (TSBs) related to this issue. Specifically, TSB 18-NA-355 (superseding earlier ones) addresses the shudder condition. It recommends a triple flush procedure using a specific new fluid, Mobil 1 LV ATF HP, which is designed to be more resistant to moisture and provide better lubrication.
  2. Fluid Flush: If your vehicle falls within the affected VIN range and mileage, a dealership will typically perform a triple flush of the transmission fluid with the updated Mobil 1 LV ATF HP. This often resolves the shudder for many owners.
  3. Torque Converter Replacement: In more severe or persistent cases, especially if the shudder returns after a fluid flush, the torque converter itself may need to be replaced. This is a more extensive repair.

When to see a shop:

You should schedule an appointment with a Chevrolet dealership as soon as possible. Explain the symptoms clearly and mention the known TSBs for the 8-speed transmission shudder. Early intervention with the fluid flush can often prevent more costly repairs like a torque converter replacement. Ignoring the shudder can lead to accelerated wear on internal transmission components.

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