Symptoms:

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

Cause:

Low signal pressure to shift solenoids A and B.

Correction:

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

4L80-E, 4L85-E

1-2 & 2-3 Shift Valve Spring Kit
Part No. 34994-02K

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In 4th Gear, signal A oil force must overpower the 1-2 shift valve spring and opposing signal B pressure in GM 4L80-E and 4L85-E transmissions. If the 1-2 shift valve does not remain fully stroked, drive oil to second and direct will be cut off or go to exhaust. The reaction area of A is greater than that of B, so the spring is the stroking factor. Complaints of 2nd Gear starts, Neutral after 2-3 shift or no 4th Gear are compounded by worn AFL limit bores, leaking O-rings and solenoids. When AFL oil drops, and signal A becomes less than 58 psi, the 1-2 valve will stall or float. This 3-1 or complaint of 3rd Neutral will occur in OD or D with scanner indication of 4th commanded. Sonnax 1-2 and 2-3 shift valve spring kit 34994-02K replaces the original 1-2 shift valve spring and 2-3 shift valve spring.

  • Set allows salvage of stripped cores
  • Restores signal pressure to shift solenoids
  • Improves shift

Springs MUST be used together. This is not a fix for leaking solenoids or leaking seals in the solenoid signal circuitor actuator feed limit circuit. See AFL limit valve repair 34200-16K.

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

Sonnax valve body layouts provide a detailed overview of individual units making it quick and easy to determine what’s available for the specific valve body you’re working on. See all Sonnax valve body layouts.

GM 4L80-E, 4L85-E, 400 Valve Body Layout

GM 4L80-E, 4L85-E, 400 Valve Body Layout
  • 4L80-E, 4L85-E 1-2 & 2-3 Shift Valve Spring Kit 34994-02K
  • 4L80-E, 4L85-E 1-2 & 2-3 Shift Valve Spring Kit 34994-02K