Secondary Regulator Valves Archives - Transmission Digest
TransGo releases S4 regulator valve for 2018-on GM 8L45, 8L90

TransGo highlights its new oversize S4 regulator valve for 2018-on GM 8L45 and 8L90 transmissions. According to TransGo, when General Motors made a change to the S4 regulator valve in both the 8L45 and 8L90 transmissions, the updated two-land design and computer command strategy resulted in significant increased wear, even at low mileage. TransGo says

Hydraulics Fundamentals: Secondary Regulators

Jim Dial discusses the importance of understanding hydraulics when working with transmissions.