Symptoms:

Burnt clutches
Pressure loss
Poor shift quality

Cause:

Wear of the 2-3-4-6-8 (S4) clutch control valve and bore can allow clutch apply fluid pressure to leak, resulting in pressure loss, a burnt clutch and poor shift quality.

Correction:

Restore proper hydraulic control and renew clutch apply fluid pressure performance by replacing worn OE parts with Sonnax drop-in S4 clutch control valve kit.

8L45, 8L90

S4 Clutch Control Valve Kit
Part No. 154740-24K

Fits '19-later units.

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Pressure loss, a burnt 2-3-4-6-8 (S4) clutch and poor shift quality are common complaints with the GM 8L45 and 8L90 transmissions. These symptoms can be caused by a worn S4 clutch control valve and bore that allows valuable clutch apply fluid pressure to leak, reducing the force needed to apply the clutch. Sonnax S4 clutch control valve kit 154740-24K is a drop-in valve with an added scarf-cut seal at the signal apply end and a lengthened inboard spool at the clutch apply end that seals worn bores and restores proper hydraulic function.

Hardcoat anodized aluminum valve combats premature wear
Lengthened valve spool utilizes unworn bore section to seal apply oil
Annular grooves help center the valve in the bore to reduce future side-load wear
Scarf-cut seal prevents leaks at the signal apply end for proper clutch control
Drop-in Zip Valve™ parts install quickly and easily

Learn More About Zip Valve™ Drop-In Repairs

Note

Early-design valve bodies have a different design S4 valve. This Sonnax valve in this kit can not be used in the early S4 location.

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