GM Service Manual Online
For 1990-2009 cars only

No 4th or Slipping 4th

Checks

Causes

Checkball #2, 4, 8 or 12

Valve body checkball in wrong location or an additional checkball is installed. Refer to Control Valve Body Installation .

Orificed Cup Plug (240)

Not fully pressed into pump cover. Refer to Oil Pump Stator Shaft Bushing Replacement .