1st-2nd & 2nd-3rd Shift Valve Spring Kit Sonnax 4L80E 4L85E

Sonnax 1-2 & 2-3 Shift Valve Spring Kit for 4L80-E, 4L85-E

In GM 4L80-E and 4L85-E transmissions, proper 4th gear operation relies on signal A oil force overpowering the 1-2 shift valve spring and signal B pressure. If the 1-2 shift valve doesn't fully stroke, drive oil to the second and direct will be compromised, leading to issues such as 2nd gear starts, neutral after 2-3 shift, or no 4th gear. These problems are often compounded by worn AFL limit bores, leaking O-rings, and solenoids. Sonnax 1-2 and 2-3 shift valve spring kit 34994-02K replaces the original springs to restore proper signal pressure and improve shifting.

Benefits:

• Allows salvage of stripped cores
• Restores signal pressure to shift solenoids
• Improves shift performance

Note:

Springs must be used together. This kit does not fix leaking solenoids or seals in the solenoid signal or actuator feed limit circuits. For AFL valve repair, see kit 34200-16K.

Kit Contents:

• 1-2 Shift Valve Spring
• 2-3 Shift Valve Spring

Symptoms Addressed:

• Repeated Solenoid B codes 86 & 87
• 2nd Gear starts
• No 4th Gear
• 3-4 Neutral
• No 3rd Gear

Cause:

Low signal pressure to shift solenoids A and B.

Correction:

Recalibrated springs for 1-2 and 2-3 shift valves.

Transmissions: 4L85E (MN8) 1991-UP, 4L80E (MT1) 1991-UP