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  • Engine surge at idle
  • Low cooler flow


Low converter release pressure at idle.


This Sonnax kit allows the rebuilder to restore correct clearances for proper hydraulic control.

4L80-E, 4L85-E

Oversized Line-to-Lube Pressure Regulator & Boost Valve Kit
Part No. 34200-36K

Fits '99-later units.

You need this if... View Instructions

GM 4L80-E and 4L85-E pressure regulator valve design prevents adequate cooler flow at low RPM and high pressure/demand conditions, which can cause overheat complaints. In ‘99-later vehicles, the factory EPC pressure was set high at idle, resulting in engine surge conditions. Sonnax oversized line-to-lube pressure regulator and boost valve kit 34200-36K provides a significant increase in cooler flow under low RPM and high pressure conditions.

  • Oversized pressure regulator valve has an encapsulated check valve that allows regulated flow to the converter charge/lube circuit at vehicle idle
  • Check valve prevents converter or pump drainback
  • Improves converter release pressure
  • End Plug
  • Pressure Regulator Valve
  • Pressure Regulator Spring
  • Boost Valve
  • Boost Sleeve

February 21, 2013

GM 4L80-E Vacuum Test Guide

Topics: Vacuum Testing Vacuum Test Guides Transmission GM 4L80-E Transmission

Read Now

  • 34200 36k combo
  • 34200 36k

You need this if...

Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.

  • 34200 36k in test