REGULATOR VALVE KIT S4 (8L90) O/S
# 128764K

Oversized S4 Regulator Valve Kit

REGULATOR VALVE KIT S4 (8L90) O/S

New oversize S4 regulator valve for GM 8L45 and 8L90 solves significant wear issues at the S4 regulator valve position.

8L45/8L90 S4 Regulator Valve
Early 3-land style
8L45/8L90 Early 3-land style S4 Regulator Valve
Late 2-land style
8L45/8L90 Late 3-land style S4 Regulator Valve

When General Motors made a change to the S4 regulator valve in both the 8L45 and 8L90 transmissions, the updated 2-land design and computer command strategy resulted in significant increased wear, even at low mileage.

TransGo redesigned this 2-land style S4 valve with an oversize hardened steel valve, lengthening the land on the spring side to ride in an unworn portion of the bore, restoring hydraulic integrity of the circuit and sealing the signal oil side with a PTFE ring to ensure longevity.


Corrects/Prevents/Reduces:

  • Slip 1-2 or 1-3 shift
  • Harsh 1-2 or 1-3 shift
  • Coast downshift clunks

Requires T-128764K

128764K TransGo Installation Instructions

Type of Product: Sundry Parts
Qty Needed:
Years:
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