Sonnax Smart-Tech® Overrun Clutch Valve Kit

Insufficient holding power in the overdrive roller clutch is the underlying cause of chronic overdrive roller clutch failure in hardworking 4L80-E and 4L85-E transmissions. When the roller clutch fails, the damage can be catastrophic and the only fix is replacing the drum, planetary assembly and mating components.

The Sonnax Smart-Tech overrun clutch valve kit 34200-40K offers a hydraulic solution to this known mechanical problem. This patent-pending kit keeps the overrun clutch applied, allowing the clutch to share a load the OD roller clutch otherwise struggles with on its own.

  • Improves OD roller clutch holding power in lower gears
  • Extends the life of workhorse transmissions while preventing warranty claims and comebacks
  • Installs quickly onto the valve body — no transmission removal needed


For more information on this product, click here to take a look at Sonnax's Smart-Tech overrun clutch valve kit full product description.