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  • 3-4 Clutch burned
  • Reduced band life
  • Soft slide shifts


MTV boost loss and insufficient line rise.


These replacement assemblies prevent oil loss between the outside diameter of the TV sleeve and the pump body.

200-4R, 4L60

TV Boost Valve Kit
Part No. 77917-01K

.423" Dia., O-Ring style

View Instructions

A common problem in 4L60 transmissions is burned bands and/or 3-4 clutches. This failure can be reduced by eliminating throttle boost oil leakage. The Sonnax replacement assemblies 77917-01K (.423" diameter), 77917-471 (.471" diameter) and 77917-500 (500" diameter) eliminate these problems for a variety of applications.

  • Throttle valve boost valve and sleeve are made from made from hardened steel for better wear resistance.
  • O-rings on sleeve separate throttle pressure and reverse boost circuits, providing additional protection against cross leaks.
  • O-rings prevent loss of oil between the outside diameter of the throttle valve sleeve and pump body.
  • Boost Valve
  • Boost Sleeve
  • O-Rings (2)
  • 77917 01k