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Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1734 (Automatic Transmission - 6L45/6L50/6L80/6L90 - Symptom Troubleshooting And Diagnosis) >> Harsh Garage Shift

Harsh Garage Shift

WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
Checks Causes
Engine Elevated engine RPM - Verify correct engine operating rpm per application.
A/Trans Fluid Pump Cover Assembly (219)
  • Inspect for damaged, stuck, sticky pressure regulator valve (233) and springs (234 and 235).
  • Inspect for damaged, stuck, sticky isolator valve (236) and sleeve (237).
Control Solenoid (w/Body and TCM) Valve Assembly (314)
  • Incorrect or inadequate adapt activity - Perform Service Fast Learn Adapts  procedure.
  • Incorrect TCM temperature reporting - Monitor TCM temperature using Tech 2.
  • Line pressure control solenoid incorrect pressure.
1-2-3-4 and 3-5-R Clutch Assembly (51)
  • Inspect for damaged 1-2-3-4 clutch piston (414), piston housing (417), spring (413), and dam assembly (412).
  • Inspect for cut, worn, or damaged 1-2-3-4 clutch piston seal (416), inner seal (423), and housing seals (424 and 425).
  • Inspect for improper selective 1-2-3-4 clutch backing plate retaining ring (429).
  • Inspect for damaged 3-5-R clutch piston (421), apply ring (405), and spring (420).
  • Inspect for cut, worn, or damaged 3-5-R clutch piston dam O-ring seal (418), inner seal (419), and outer seal (422).
  • Inspect for improper selective 3-5-R clutch backing plate retaining ring (400).