For 1990-2009 cars

#### No Fourth Gear, Slips in Fourth Gear

Checks | Causes
--- | ---
Intermediate/Fourth Band & Servo | No apply or slipping
Servo Piston (77) | Broken or binding
Servo Piston Seals (78, 79) | Leaking
Servo Pin (76) and Springs (78, 79) | Binding
Servo Cover (80) | Broken, loose, or leaking
Band (100) | Broken, worn, or out of position
Case (1) | Cracked at the band seat
Band Apply Fluid Routing | Fluid leak and fluid restricting

• | Valve Body

• | Gaskets & Spacer Plate

• | Channel Plate

• | Case

• | Porosity

• | Misalignment

• | Fluid leak across the channels

1-2 Shift Solenoid Valve (305) |

• | Stuck OFF

• | Leaking

3-4 Shift Valve (319) | Stuck in the downshifted position
Manual Valve (800) | Misaligned in Manual Third gear
3-4 Accumulator |

• | A leak at the piston seal

• | Channel plate or case porosity

3-4 Accumulator Valve (323) | Stuck
Line Pressure | Low pressure Refer to High or Low Line Pressure .
Direct Clutch | A low capacity will cause a failure in the Fourth gear
PSA | Hydraulic or electrical malfunction