Sonnax 4th gear super hold dual servo kit features 40% more apply surface area for greater holding power in GM 4L60, 4L60-E, 4L65-E and 4L70-E units.

Vehicles with these transmissions often exhibit poor 3-4 shift quality and experience band failure in performance applications.

Dual-piston design with 40% more apply delivers greater holding power

D-ring seals prevent pressure loss

Use with OE, Corvette or Sonnax 2nd gear servo assemblies