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 End plug manufactured from highly wear-resistant aluminum O-Rings positively seal bore to prevent leakage Drop-in Zip Valve™ parts install quickly and easily Contents End Plug End Plug O-Ring AFL Filter O-Ring