In Chrysler 48RE transmissions, the cooler/converter charge circuit is not opened until the pressure regulator valve moves far enough to flow oil. The industry fix of drilling a small orifice between line pressure and cooler circuit ensures flow to the converter/lube circuit, but the hole also increases the converter drain back problem because ATF can drain when the engine is turned off.
Sonnax offers oversized lube regulated pressure regulator valve and line/TV pressure plug kit 22771A-16K that allows rebuilders to salvage worn valve bodies.
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.
Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.