Automatic Transmission

Symptom Troubleshooting Index (cont'd)

 14-15  

Symptom Probable cause(s) Notes
Late shift from position to and positions
  1. 1st clutch defective
  2. Foreign material in 1st orifice
  • 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 1st clutch pressure.
Late shift from position to position
  1. Shift fork shaft stuck
  2. 4th clutch defective
  3. 1-2 shift valve defective
  4. Servo control valve defective
  • Check for a missing shift fork bolt on the shift fork shaft.
  • Inspect the servo valve and the O-ring.
  • 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 4th clutch pressure.
No shift
  1. A/T clutch pressure control solenoid valve A defective
  2. CPC valve defective
  3. Modulator valve defective
  4. Shift solenoid valve A defective
  5. Shift solenoid valve B defective
  • 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 A is stuck, inspect the CPC valve.
  • Check the * indicator light indication and check for loose connectors. Inspect the shift solenoid valve filter/gasket and the shift solenoid valves A and B for seizure.
  • If the ATF strainer is clogged with particles of steel or aluminium, inspect the ATF pump. If the ATF pump is OK and no cause for the contamination is found, replace the torque converter.
Erratic shifting gears:

Fails to shift in and positions; shifts from 1st 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 shifting gears:

Fails to shift in and positions; shifts from 1st to 4th gear
  1. 2-3 shift valve defective
  2. 3-4 shift valve defective
  3. 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.