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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different car >> Section 57 (Automatic Transmission - 8L90 (M5U) - Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> DTC P0776 or P0777 >> Diagnostic Fault Information

Diagnostic Fault Information

WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
  • DTC P0776, P0777 sets only when there is a hydraulic/mechanical problem.
  • The components are listed from the least to the most intrusive to service.
  • Verify the conditions listed in the table do not exist:
Component DTC Condition
Q77B Transmission Control Solenoid Valve 2 P0776, P0777
  • Binding, sticking or stuck component: Solenoid Valve
  • Damaged or missing component:
    • Retaining Clip
    • Solenoid Valve
1-2-3-4-5-RClutch Regulator Valve P0776, P0777
  • Blocked or restricted component: Screen - Fluid/oil passage
  • Binding, sticking or stuck component: Valve
  • Debris on the component.
  • Damaged component:
    • Valve or Bore - Scored
    • Spring
1-2-3-4-5-R Clutch Assembly P0776, P0777
  • Blocked or restricted component: Fluid/oil passage
  • Leaking component:
    • Clutch Piston
    • Clutch Housing
    • Gasket
    • O-Ring
    • Seal
  • Binding, sticking or stuck component: Clutch Plates
  • Damaged or worn component:
    • Clutch Plates
    • Clutch Piston
    • Clutch Housing