As used with Shelby Mustang and other performance vehicles, Sonnax "C" ratio servo kit K13259C offers greater holding power, giving cleaner, firmer 1-2 and 2-3 shifts. Machined from 6061 aluminum billet, this servo features lip seals on the piston for superior sealing over a wide range of fluid pressure. This is the largest in the C4 servo family and works equally well in performance C5 applications. The servo pin incorporates two PTFE sealing rings to insure the hydraulic integrity of the pin in worn cases. Cleaning up a 2-3 flare was never easier than installing this servo.

Sonnax also offers a replacement seal kit K13259C-SK and a lip seal retrofit kit K13259C-SKR to convert older Sonnax servos to the new lip seal configuration.