🚗 Classic Fault — Triumph CP/CR (1969–1976)
Triumph TR6 overdrive not engaging
💰 Estimated Repair Cost
$50 – $400 GBP
Parts and labour estimate
🔧 Tools Required
Gearbox oil tools, multimeter
📋 Overview
The Laycock overdrive unit on the TR6 fails to engage due to low oil, failed solenoid or worn clutch.
🩺 Symptoms
- Overdrive switch has no effect
- overdrive engages then drops out
- overdrive slips under load
🔍 Possible Causes
- Low overdrive oil
- failed overdrive solenoid
- worn overdrive clutch pack
- faulty overdrive switch
🛠️ Diagnosis Steps
Check gearbox oil level first — low oil causes overdrive failure. Test solenoid with direct 12V.
✅ Most Confirmed Fix
Overdrive solenoid replacement or unit rebuild
78% of users confirm this fix worked (19 reports)
🔗 Other Triumph CP/CR Faults
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