• Broken AFL filters
  • 2nd Gear starts
  • Leaking AFL end plug
  • Code 68, 85, 86, 87
  • No upshifts


Damaged AFL filter or leaking end plug causes driveability problems and/or trouble codes.


Renew AFL operation and restore shift control by installing Sonnax AFL filter end plug & O-ring kit.

4L80-E, 4L85-E

AFL Filter End Plug & O-Ring Kit
Part No. 34994-17K

View Instructions Find a Distributor

GM 4L80-E and 4L85-E transmissions may have 2nd gear starts and no upshifts, which can be accompanied by trouble codes 68, 85, 86 and/or 87. These problems can often be traced to a leaking actuator feed limit (AFL) filter or end plug. Installing Sonnax AFL filter end plug and O-ring kit 34994-17K eliminates these problems by restoring hydraulic control to the circuit.

For a more comprehensive AFL circuit repair, recommend also installing Sonnax actuator feed limit valve kit 34200-16K.

  • End plug manufactured from highly wear-resistant aluminum
  • O-rings positively seal bore to prevent leakage
  • End Plug
  • End Plug O-Ring
  • AFL Filter O-Ring

February 21, 2013

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  • 34994 17k combo
  • 34994 17k