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Home >> Chevrolet >> 2012 >> Tahoe Base, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1728 (Automatic Transmission - 4L60-E/4L65-E/4L70-E - Symptom Troubleshooting And Diagnosis) >> Slipping or Harsh 1-2 Shift

Slipping or Harsh 1-2 Shift

WARNING: This page is about a different car, the 2010 GMC Sierra and 2010 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
Checks Causes
Valve Body Assembly (60)
  • Mislocated valve body to spacer plate checkball or checkballs.
  • 1-2 shift valve train stuck due to sediment
  • Gaskets or spacer plate incorrect, mis-positioned or damaged
  • 1-2 accumulator valve stuck or damaged
  • Face not flat
  • 4-3 sequence valve stuck or damaged
  • #1 or #8 checkball missing or mis-located
  • 1-2 accumulator valve bushing rotated 180°
2-4 Servo Assembly (13-28)
  • Apply pin too long or too short
  • 2nd servo apply piston seal missing, cut or damaged
  • Restricted or missing oil passages
  • Servo bore in case damaged
2nd Accumulator (55-57, 104)
  • Porosity in 1-2 accumulator cover or piston
  • Piston seal or groove damaged
  • Nicks or burrs in 1-2 accumulator housing
  • Missing or restricted oil passage
  • 1-2 accumulator piston spring not seated
  • Rough finish in 1-2 accumulator bore in case
  • A cracked 1-2 accumulator piston - allowing fluid to leak by
2-4 Band (602) Worn or mispositioned
Oil Pump Assembly (4) or Case (103) Faces not flat