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Home >> GMC >> 2021 >> Terrain SLT, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 91 (Automatic Transmission - 9T45 (M3U) Or 9T50 (M3D M3H) - Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> No Reverse Gear

No Reverse Gear

WARNING: This page is about a different car, the 2020 GMC Terrain and 2020 Chevrolet Equinox. However, it is still accessible from the selected car via links, so may be relevant.
Checks Causes
Control Valve Body (23)
  • Inspect the 3-8 Clutch Regulator Valve (487) and Control Valve Body Ball Check Valve (453) for debris and stickiness.
  • Inspect the Clutch Selector Valve (467) and the Actuator Feed Limit Valve (451) for debris and stickiness.
Automatic Transmission Case (19)
  • Inspect the Input Shaft Support (54) for missing or damaged Fluid Seal Rings (56).
Low and Reverse Clutch (590)
  • Inspect for stripped or sheared splines on Low and Reverse Clutch Plates (596 - 597)
  • Inspect for damaged, deformed or improper surface finish on the Low and Reverse Clutch Plates (596 - 597)
  • Inspect for stripped or sheared splines on Low and Reverse Clutch Backing Plate (598)
  • Inspect for worn, damaged or debonding Low and Reverse Clutch Piston Seals (592)
  • Inspect for broken or fatigued Low and Reverse Clutch Piston Return Spring (593)
5-7-Reverse and 6-7-8-9 Clutch Housing (516)
  • Inspect for damaged, stripped or sheared splines on 5-7-Reverse Clutch Plate (579-580), 5-7-Reverse Clutch Backing Plate (581).
  • Inspect for stripped or sheared splines on 5-7-Reverse and 6-7-8-9 Clutch Housing (567) to Turbine Shaft (547).
  • Inspect for damage, improper surface finish, porosity, deformed or unbalanced 3-5 Rev/4-5-6 Housing (516).
  • Inspect for damaged, worn, loose or seized hub bushing in the 5-7-Reverse and 6-7-8-9 Clutch Housing (567).
  • Inspect for broken, porous or improper surface finish or plugged oil passages of the 5-7-Reverse and 6-7-8-9 Clutch Housing (567).
  • Inspect for failure of the 6-7-8-9 and 5-7-Reverse Clutch Housing Thrust Bearing (515).
  • Inspect for disengaged or broken 5-7-Reverse Clutch Backing Plate Retaining Ring (582).
  • Inspect for damaged, worn or leaking 3-5 Reverse Clutch Piston Seals (564 - 566).
  • Inspect for damaged or broken 5-7-Reverse and 6-7-8-9 Clutch Housing (567).
  • Inspect for warped, damaged, improper surface finish or debonding 3-5 Reverse Clutch Piston (562).
  • Inspect for broken or fatiqued 3-5-Reverse Clutch Piston Retainer Spring (563).
  • Inspect for disengaged or broken Automatic Transmission Input Shaft Speed Sensor Reluctor Ring Retaining Ring (560).
  • Inspect for broken Automatic Transmission Input Shaft Speed Sensor Reluctor Wheel (561).