Cold-Weather Harsh Ride and Noise on Silverado & Sierra Trucks: GM Bulletin # 25-NA-380
- Greg Nelson
- 3 days ago
- 2 min read
Updated: December 16, 2025
Bulletin: # 25-NA-380
Applies To: Chevrolet Silverado & GMC Sierra (1500 / 2500HD / 3500HD)
What Owners Are Experiencing
GM has released bulletin # 25-NA-380 addressing customer complaints that only show up in cold weather, typically below 32°F (0°C).
Reported symptoms include:
Harsh or stiff ride quality
Increased road noise entering the cab
Axle or mechanical noise that seems worse in cold temperatures
What makes this issue frustrating is that the truck may feel completely normal once temperatures rise.
Affected Vehicles
This bulletin applies to the following trucks:
Chevrolet
Silverado 1500 (2025–2026)
Silverado 2500HD / 3500HD (2025–2026)
GMC
Sierra 1500 (2025–2026)
Sierra 2500HD / 3500HD (2025–2026)
Build Window of Concern
Body mounts built October 1–20, 2025
Vehicles assembled October 1, 2025 through November 3, 2025
Assembly plants include Flint, Fort Wayne, Silao, and Oshawa
Not every truck in this range will be affected, but this build window is where GM is seeing the pattern.
Root Cause: Frozen Hydraulic Body Mounts
GM traced the issue to the #3 body mounts (rear cab mounts).
According to the bulletin, these mounts may contain an incorrect glycol mixture. In cold temperatures, that mixture can freeze, which disables the hydraulic damping function of the mount.
When that happens:
Vibration isolation is lost
Noise transfers directly from the frame into the cab
Ride quality becomes noticeably harsher
This is not a suspension failure, axle issue, or driveline defect—it’s a body-to-frame isolation problem.
Why It Sounds Like an Axle or Drivetrain Issue
When body mounts lose damping, normal road and mechanical noises that are usually absorbed get transmitted straight into the cab. To the driver, it can feel like:
Rear axle noise
Driveline vibration
Excessive road feedback
That’s why many owners initially suspect tires, shocks, differentials, or axle bearings.
GM’s Fix
Correction:Replace both left and right #3 body mounts.
GM instructs technicians to follow the SI procedure:
Body Mount Upper Location Number 3 Cushion Replacement
Only the affected mounts are replaced—this is not a full body mount kit.
Parts Information
Parts must be selected based on VIN using the EPC.
Causal Parts:
Light-duty and heavy-duty trucks use different mount assemblies.
What Owners Should Do
If your 2025–2026 Silverado or Sierra:
Feels harsh only in cold weather
Gets noticeably quieter or smoother when temperatures rise
Was built in the October–November 2025 window
This bulletin is worth referencing at the dealership.
This condition is temperature-dependent, so documenting the concern during cold conditions helps speed up diagnosis.
Final Takeaway
This is a good example of how NVH issues aren’t always suspension or drivetrain related. A frozen hydraulic body mount can completely change how a truck feels and sounds—without any warning lights or fault codes.
If your truck suddenly feels “wrong” only in winter, body mounts should be on the diagnostic list.