ASE G1 Auto Maintenance and Light RepairAutomatic Transmission/TransaxleMedium
A vehicle with an automatic transmission experiences a condition where it will not engage any forward gears, but Reverse engages and operates normally. What is the most likely cause of this specific symptom?
- ALow transmission fluid pressure due to a failing pump.
- BA failed forward clutch pack.
- CA stuck open bypass valve in the valve body.
- DA faulty vehicle speed sensor (VSS).
Show answer & explanationAnswer & explanation
Correct answer: B. A failed forward clutch pack.
If Reverse engages and operates normally, but no forward gears engage, it strongly indicates a problem specific to the forward clutch pack. The reverse circuit often uses different components or a different application of pressure than the forward gears, so its proper function rules out many common issues like low fluid or a completely failed pump.
Why the other options are wrong
- A. A failing pump would generally lead to low pressure across the board, affecting both forward and reverse engagement, or causing severe slipping.
- C. A stuck open bypass valve would likely affect overall pressure and potentially all gear engagements, not just forward gears.
- D. A faulty VSS typically causes erratic shifting or speedometer issues, not a complete loss of forward gears while reverse works.
No Forward, Yes Reverse
When an automatic transmission engages Reverse but no forward gears, it often points to a failure in the forward clutch pack or its associated hydraulic circuit.
- Indicates a specific component failure.
- Rules out general fluid level or pump issues.
- Requires transmission disassembly for repair.
Memory trick: Forward stuck, reverse quick? Forward clutch needs a fix.