## Automatic Transmission

#### Symptom Troubleshooting Index (cont'd)

14-16

Symptom | Probable cause(s) | Notes
Erratic upshift: 1st to 2nd, 2nd to 3rd and 3rd to 4th gears | Countershaft speed sensor defective | Check the indicator light indication and check for loose connectors. Check the countershaft speed sensor installation.
Erratic upshift: 1st to 2nd gear |

1. 1-2 shift valve defective
2. Shift solenoid valve A defective

Check the indicator light indication and check for loose connectors. Inspect the shift solenoid valve filter/gasket and the shift solenoid valve A for seizure.
Erratic upshift: 2nd to 3rd gear |

1. 2-3 shift valve defective
2. Shift solenoid valve B defective

Check the indicator light indication and check for loose connectors. Inspect the shift solenoid valve filter/gasket and the shift solenoid valve B for seizure.
Erratic upshift: 3rd to 4th gear |

1. 3-4 shift valve defective
2. Shift solenoid valve A defective

Check the indicator light indication and check for loose connectors. Inspect the shift solenoid valve filter/gasket and the shift solenoid valve A for seizure.
Harsh upshift: 1st to 2nd gear |

1. 2nd clutch defective
2. A/T clutch pressure control solenoid valve A defective
3. A/T clutch pressure control solenoid valve B defective
4. CPC valve defective
5. Foreign material in main orifice
6. Torque converter clutch solenoid valve defective
7. Mainshaft speed sensor defective
8. Countershaft speed sensor defective

- Inspect the clutch piston, clutch piston check valve and O-rings. Check the spring retainer for wear and damage. Inspect the clutch end plate-to-top disc clearance. If the clearance is out of tolerance, inspect the clutch discs and plates for wear and damage. If the discs and plates are worn or damaged, replace them as a set. If they are OK, adjust the clearance with the clutch end plate.
- Check the 2nd clutch pressure.
- Check the indicator light indication and check for loose connectors. Inspect the A/T clutch pressure control solenoid valve filter/gasket for wear and damage. If the A/T clutch pressure control solenoid valve is stuck, inspect the CPC valve.
- Check the indicator light indication and check for loose connectors. Inspect the O-rings and check the torque converter clutch solenoid valve for seizure.
- Check the mainshaft speed sensor installation.
- Check the countershaft speed sensor installation.