GM Service Manual Online
For 1990-2009 cars only

No Fourth Gear -- D4

Checks

Cause

Fourth Clutch Components

  • Seals (527) (531)

Nicked or cut

  • Cup Plug (530)

Missing

  • Bolt (26)

Loose, broken, or missing

  • Piston (528)

Jammed

  • Spring Assembly (532)

Jammed

  • Retainer Ring (523)

Not seated

  • Friction Plates (525)

Worn or burned

  • Reaction Plates (526)

Worn splices

  • Housing (529)

Damaged or cracked

Overrun Clutch Components

  • Housing (504)

Broken

  • Reaction Plates (508)

Worn splines

  • Sun Gear (650)

Worn

  • 1-2 Solenoid (313)
    • Stuck Off
    • Pinched wire
    • O-ring failure
    • No voltage to the solenoid
  • VCM/PCM

No signal to the solenoid

  • 3-4 Shift Valve (308)

Stuck

  • Quad Driver Module

Failed

Check the VCM/PCM for current DTCs