P1778 RE5R05A Patrol Y61
P1778 RE5R05A Patrol Y61
P1778 RE5R05A – Is It Just a Solenoid or the Start of a Bigger Problem?
What Does P1778 Mean?
The P1778 code on vehicles equipped with the RE5R05A 5-speed automatic transmission (found in Nissan Patrol Y61, Pathfinder R51, Navara D40, and Infiniti FX/QX) signals a torque converter lock-up performance problem or control solenoid fault.
While some drivers hope it’s “just a solenoid,” this code is usually a symptom of deeper problems, like torque converter clutch wear or valve body cross-leak, which affect line pressure and smooth lock-up.
Typical Symptoms of P1778
Light shudder or vibration during highway cruising (80–100 km/h).
Harsh or delayed shifts, especially 2nd–3rd under load.
RPM fluctuations while maintaining steady throttle.
Heat build-up or overheating warning lights on heavy trips.
Fluid that is dark or smells burnt, often with fine metallic debris.
What Causes P1778?
1. Torque Converter Lock-Up Clutch Wear: The TCC lining deteriorates, causing slip and heat.
2. Valve Body Solenoid Fault: Solenoids fail due to bore wear and fluid contamination.
3. Pressure Leaks: Cross-leaks in the valve body reduce TCC holding power.
4. Fluid Breakdown: Overheated fluid reduces lubrication and accelerates wear.
What Happens If You Ignore It?
Torque converter failure progresses, leading to P0741 lock-up faults.
Rear clutch pack (C2/C3) damage due to prolonged slipping.
Full transmission failure, requiring a costly rebuild.
The Redorq Solution for P1778
Our $285 Redorq Scan + Dyno Diagnostic pinpoints whether P1778 is caused by solenoid wear, torque converter slip, or line pressure faults.
The recommended TQ+VB rebuild package includes:
• Remanufactured HD Torque Converter – with upgraded lock-up clutch lining.
Valve Body rebuild or exchange – correcting solenoid faults and cross-leaks.
Full clutch pack replacement (C1–C3) if necessary.
Transmission cooler upgrade to prevent heat-related repeat failures.
Pre- and post-repair dyno tests for complete validation.
Typical cost: $4,700 – $5,300 inc GST for a complete TQ+VB rebuild including cooler upgrade.
Why Choose BTT for P1778 Repairs?
Specialists in RE5R05A transmissions for Patrol, Pathfinder, Navara, and Infiniti FX/QX.
Dyno-based fault confirmation eliminates guesswork.
Upgraded solutions designed for towing, off-road, and high-heat conditions.
Book Your Scan + Dyno Today
Don’t gamble on whether P1778 is just a solenoid — often, it’s the start of something bigger. Call Brisbane Tuning & Turbo or Book Online now to schedule your $285 Redorq Scan + Dyno Diagnostic. Click here to get our contact details.
P0741 Nissan Patrol – The Lock-Up Code That Signals Converter Failure.
Pathfinder R51 Transmission Problems – What Every Owner Should Know.
RE5R05A Transmission.
