ASE G1 Auto Maintenance and Light RepairAutomatic Transmission/TransaxleMedium
A customer complains that their automatic transmission sometimes 'hangs' in a gear, staying in a lower gear longer than expected before eventually shifting. This happens intermittently. A scan tool shows no active DTCs. What is the most likely cause?
- AAn intermittently sticking shift solenoid.
- BA partially clogged transmission cooler.
- CA faulty transmission output shaft speed sensor.
- DIncorrectly adjusted shift linkage.
Show answer & explanationAnswer & explanation
Correct answer: A. An intermittently sticking shift solenoid.
An intermittently 'hanging' transmission, where it delays shifting to the next gear, is a classic symptom of a sticking or intermittently faulty shift solenoid. Shift solenoids are electrically operated valves that control fluid flow to apply or release clutch packs, determining gear engagement. If one sticks, it can delay the commanded shift.
Why the other options are wrong
- B. A clogged cooler leads to overheating and potential slipping, not typically hanging in a gear intermittently.
- C. A faulty output shaft speed sensor would cause erratic shifting, speedometer issues, or torque converter lock-up problems, but usually not just 'hanging' in a lower gear.
- D. Incorrectly adjusted linkage usually causes issues with selecting gears (e.g., P not engaging, D starting in 2nd), not hanging within a gear once engaged.
Sticking Shift Solenoid
An intermittently sticking or faulty shift solenoid can cause an automatic transmission to 'hang' in a gear, delaying the commanded upshift or downshift.
- Solenoids control fluid flow for shifts.
- Intermittent issues often point to sticking.
- Can occur without setting a DTC initially.
Memory trick: Delayed shifts? Solenoid's stuck, can't make it quick.