Most GM vehicles with hydraulic power steering use Dexron VI ATF-based power steering fluid. Some older GM models require GM Power Steering Fluid or Dexron II/III-based fluids. Electric power steering systems do not require PSF. Always check your vehicle’s owner’s manual or GM service information for the exact specification.
GM's Fluid Specifications: What to Know
The guidance GM offers varies by model year, engine, and whether the car uses hydraulic or electric power steering. The most common, modern requirement is Dexron VI-based power steering fluid, compatible with Dexron VI ATF.
- Dexron VI ATF-based power steering fluid is the standard for most modern GM vehicles with hydraulic steering.
- Older GM vehicles may require GM Power Steering Fluid or Dexron II/III-based fluids, depending on the design and year.
- Electric power steering systems in some GM vehicles do not use hydraulic PS fluid at all and rely on electrical control instead.
Because compatibility can vary by model and VIN, always verify with the owner's manual, a GM dealer, or GM's service information system before filling or topping off.
Dexron VI: The Modern Standard
Dexron VI is GM's recommended standard for hydraulic PS systems in most post-2007 GM models. It is an ATF formulation designed to handle the friction-modifier and viscosity needs of steering gear while offering better high-temperature performance than earlier Dexron variants.
- Dexron VI is the widely used specification in 2007 and newer GM vehicles with hydraulic steering.
- Using Dexron VI will typically be compatible with older Dexron II/III systems due to GM's backward compatibility guidance, but always confirm with the vehicle's manual.
- OEM and aftermarket Dexron VI fluids marketed for PSF are common and often cross-compatible with GM PS systems.
Misusing fluids can cause foaming, steering stiffness, leaks, or wear; always follow GM's guidance for your exact model.
Older GM Vehicles: GM PSF and Dexron II/III
In older GM designs, the power steering system may have used GM Power Steering Fluid or Dexron II/III ATF-based fluids. These formulations are distinct from Dexron VI and have different additive packages.
- GM Power Steering Fluid was a dedicated product used in some older GM hydraulic systems.
- Dexron II/III ATFs were used in some earlier steering gear applications and may not be compatible with modern PS components.
- When preserving an older GM vehicle, use the exact specification called out by GM for that year and model.
When in doubt, consult the owner's manual or a GM-certified technician to avoid compatibility issues.
Special cases: Electric Power Steering
Many newer GM vehicles employ electric power steering (EPS) that does not require a hydraulic power steering fluid. These systems rely on electric motors and sensors; do not add PS fluid to EPS-equipped vehicles unless the manual explicitly instructs you to.
In hybrids or certain models still featuring hydraulic EPS, you may see specific guidance; always verify.
Summary
GM's current guidance centers on Dexron VI ATF-based power steering fluid for most hydraulic systems in post-2007 models, with older vehicles sometimes requiring GM PSF or Dexron II/III. EPS models do not use PSF. Always verify the exact specification for your vehicle via the owner's manual or GM service information to ensure optimal performance and safety.