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  • 3-4 Clutch failure
  • Clutch slippage
  • Excess pump noise
  • Low line rise
  • Reverse chatter


Pressure regulator valve bore wear allows leakage and contributes to erratic pump slide movement.


Repair the valve bore and restore pressure control to the system with this oversized pressure regulator valve and reamer kit.

200-4R, 4L60

Oversized Pressure Regulator Valve
Part No. 77917-06

You need this if... View Instructions

A worn OE pressure regulator valve can be detected in two ways. The first is a dynamometer test that reveals low line pressure during boost conditions (look for 50-100 psi less than specified in Reverse). The second is vehicle symptoms such as clutch slippage, reverse chatter and 3-4 clutch failure. Any of the above problems indicate bore wear that should be addressed.

To address pressure regulator leakage in GM 4L60, 200-4R pump covers, Sonnax offers oversized pressure regulator valve 77917-06. The Sonnax valve permits pump covers to be restored to OE specifications by correcting for wear and leakage at the pressure regulator valve.

  • Refurbish the pump cover by reaming the bore and installing an oversized pressure regulator valve
  • The pressure regulator valve helps restore control over the pressure regulating circuit by eliminating leakage

Boost valves should be checked for leakage at the same time the pressure regulator valve is being replaced.

March 02, 2016

Building the Killer 4L60-E

Topics: Diagnostics And Theory Rebuilding Tips Transmission GM 4L70-E Transmission 4L60 Transmission 4L60-E Transmission 4L65-E Transmission

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  • 77917 06 combo
  • 77917 06

You need this if...

  • 77917 06 in test