April 16, 2024
Watch Out for High Pressure in GM 8L45, 8L90 Valve Bodies
Chris Leach
Symptoms:
- No movement
- Damaged valve body casting
- Broken parts due to excessive line pressure
- Erratic line pressure
Cause:
The OE blow off spring doesn't relieve pressure effectively until 400+ psi. This high pressure can cause damage to the worm tracks of the valve body where cracks/breaks can be formed.Correction:
Restore proper function of the blow-off spring by replacing the overpowered OE spring with lighter acting, Sonnax pressure relief ball valve spring.8L45, 8L90
Pressure Relief Ball Valve Spring
Part No. 154740-18
Package Quantity: 5
View Instructions Find a DistributorThe GM 8L45 and 8L90 transmissions are having a recurring problem where the typical ball and spring seat is not opening and relieving pressure effectively. The OE spring design needs to see 400+ psi in order to open and relieve line pressure. As a result of this high pressure not being relieved, damage/cracks to the worm tracks can occur.
Sonnax pressure relief ball valve spring 154740-18 allows line pressure to exhaust between 300–325 psi which will prevent future cracking of the worm tracks and restore proper function of the blow-off ball and spring.
