700R4 4L60 4L60E 4L65E 4L70E Transmission 4th Gear Super Hold Servo Vehicles with a 4L60 or 4L60-E family transmission often exhibit poor 3-4 shift quality and experience band failure in performance applications. The Sonnax "Super Hold" 4th Gear Servo features 40% more apply surface area for greater holding power 40% more surface area for greater holding power Billet Aluminum for super strength and durability Affects 4th gear only Can be used with OEM, Corvette or Sonnax performance 2nd gear servo assemblies Easy to install: Transmission removal is not required Excellent choice for vehicles used for highway towing Gives firmer 3-4 shift