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  • High line pressure in Reverse
  • Erratic line pressure
  • No line rise
  • Delayed engagement
  • Engine stall at idle


Wear at the boost regulator bore or the large end of the main regulator valve can cause low line pressure. Wear at the inboard end of the main regulator valve causes high line pressure.


Sonnax now offers an oversized valve kit for both the main regulator valve and the boost regulator valve with improved boost oil circuit and improved converter feed.

01M, 01N, 01P

Oversized Boost Regulator Valve Kit
Part No. 119940-05K

View Instructions

If regulated line leaks to exhaust at the pressure regulator, it creates a low pressure condition. Wear at the inner balance spools prevent the valves from stroking, which can cause high line pressure. Wear at the inboard bore also affects the K1 clutch circuit, which can result in 1-2 or 2-3 shift complaints. Wear at the inboard end of the boost regulator bore can reduce the ability of EPC/TV pressure to stroke this valve open. Full boost exiting this valve combines forces with the main regulator spring, increasing line pressure. Sonnax offers oversized valve kits for both the main regulator valve, 119940-03K, and the boost regulator valve, 119940-05K. These kits allow the valve bores to be refurbished.

  • Oversized hard-coat anodized aluminum valves restore hydraulic integrity of the circuits andprevent wear.
  • The main regulator valve kit contains an o-ringed end plug to positively seal the bore and prevent regulated boost line pressure from exhausting.
  • A new spring is included to work with the oversized valve and re-establish OEM regulated pressure specifications.
  • A replacement ratcheting end plug is included in the boost regulator kit, as the OEM one often breaks.
  • An adjustment tool is provided in the boost regulator tool kit for repeated assembly, disassembly and adjustment of the ratcheting end plug.
  • Valve
  • Ratcheting Plug
  • 119940 05k combo
  • 119940 05k