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  • Broken parts due to excessive line pressure
  • Erratic line pressure
  • High line pressure
  • Restricted converter/lube flow


Excess pressure regulator sleeve wear allows fluid loss and/or causes valve hang-up, preventing normal line pressure control.


Restore appropriate line pressure in all ranges by installing wear-resistant Sonnax pressure regulator sleeve.

ZF8HP45, ZF8HP55, ZF8HP70

Pressure Regulator Sleeve
Part No. 35740-03

You need this if... View Instructions

Vehicles equipped with ZF8HP45, ZF8HP55 and ZF8HP70 transmissions often develop erratic or high line pressure due to excessive wear in the OE pressure regulator sleeve. This wear allows balance oil loss, preventing proper line pressure regulation. Without correct balance oil pressure, the PR valve will be out of its desired position, resulting in line pressure instability and possibly restricting cooler and lube flow. Installing Sonnax pressure regulator sleeve 35740-03 renews pressure regulator action for revived line pressure control in all ranges.

  • Manufactured from highly wear-resistant aluminum
  • No machining or special tools required

Sonnax valve body layouts provide a detailed overview of individual units making it quick and easy to determine what’s available for the specific valve body you’re working on. See all Sonnax valve body layouts.

ZF8HP55 Valve Body Layout

Zf8hp55 vbl thumb

ZF8HP45, ZF8HP70 Valve Body Layout

Zf8hp45 70 vbl thumb

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  • 35740 03 combo
  • 35740 03

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.

  • 35740 03 test