For 1990-2009 cars

Checks | Causes
--- | ---
DEFINITION: A large engine RPM increase is noted in first gear, Drive range, with little or no vehicle forward speed increase. Second, third, and fourth gear operations are normal. Shifts into first gear are soft or do not occur. First gear ratio is 2.921:1
Forward Clutch |

• | Clutch plates worn

• | Porosity in the piston

• | Piston seal damaged

• | Forward clutch housing ball check valve not sealing or damaged

• | Input shaft fluid seals damaged or missing

Control Valve Body Accumulator Assembly |

• | Face not flat

• | Spacer plate or gaskets mispositioned or damaged

Input Sun Gear Shaft | Broken shaft
Forward Sprag Clutch Assembly | Sprags not holding
Low Clutch Sprag Assembly | Sprags not holding
Torque Converter Assembly | Stator roller clutch not holding
Line Pressure | Refer to Fluid Pressure High or Low .