The 2017 QX50 uses Nissan's VQ37VHR 3.7L V6 paired with a 7-speed automatic (RE7R01A). The engine is generally solid, but the transmission has known internal failures and cooling issues that dominate the repair history for this platform.
Transmission Oil Cooler Failure & Contamination
Common · high severityTypical onset: 60,000-110,000 mi
Symptoms: Transmission fluid mixed with coolant (strawberry milkshake in expansion tank), Harsh shifts or slipping between gears, Transmission overheating warning on dash, Coolant loss with no visible leaks
Fix: Replace transmission oil cooler and flush both cooling and transmission systems. If contamination reached transmission internals, full rebuild or replacement required. Oil cooler replacement alone: 3-4 hours. If trans damaged: 12-18 hours for R&R and rebuild.
Estimated cost: $800-1,200 (cooler only), $4,500-7,500 (if transmission rebuild needed)
RE7R01A Transmission Internal Failures
Occasional · high severityTypical onset: 80,000-140,000 mi
Symptoms: Limp mode with P0868 or P17F0 codes (line pressure), Delayed engagement into drive or reverse, Harsh 2-3 or 3-4 upshifts, Slipping under load or on highway merges
Fix: Common issues include valve body wear, clutch pack failure (especially C2/C3), and solenoid faults. Full rebuild or reman unit required. Remove and reinstall: 10-12 hours. Rebuild adds another 14-18 hours if done in-house.
Estimated cost: $3,800-6,500
Transmission Mount Deterioration
Common · low severityTypical onset: 70,000-120,000 mi
Symptoms: Clunk or thud when shifting from park to drive, Vibration at idle in gear, Excessive driveline movement felt during acceleration
Fix: Replace rear transmission mount. Access requires raising vehicle and supporting transmission. 1.5-2 hours labor.
Estimated cost: $250-450
VQ37 Timing Chain Galley Gasket Leak
Occasional · medium severityTypical onset: 90,000-150,000 mi
Symptoms: Oil seepage at front of engine below timing cover, Oil consumption (1 qt per 2,000-3,000 miles), Timing chain noise on cold start if oil level drops
Fix: Replace timing chain galley gaskets (front cover area). Requires timing cover removal, timing chain inspection, and front main seal. 8-10 hours labor.
Estimated cost: $1,800-2,800
Fuel System (High-Pressure Pump & Injectors)
Occasional · medium severityTypical onset: 100,000-160,000 mi
Symptoms: Long crank or hard start when hot, P0087 code (fuel rail pressure too low), Rough idle or misfire at idle only, Loss of power under throttle
Fix: High-pressure fuel pump (cam-driven) or direct injectors fail. Pump replacement: 4-5 hours. Injector set (all six): 5-6 hours. Diagnosis critical — don't shotgun parts.
Estimated cost: $1,200-1,800 (pump), $1,800-2,800 (injectors)
Engine Rebuild Scenarios (Rare but Documented)
Rare · high severityTypical onset: 150,000+ mi or abuse-related
Symptoms: Rod knock or main bearing noise, Heavy blue smoke from exhaust (ring failure), Severe loss of compression across multiple cylinders, Metal in oil or catastrophic oil starvation event
Fix: VQ37 can suffer bearing failures if oil changes are neglected or if severe overheating occurs. Requires short block or full rebuild. Remove/install engine: 18-22 hours. Machine work and rebuild adds significantly to cost.
Estimated cost: $6,500-12,000
Decent luxury crossover if you find one with documented transmission services and no cooler contamination history — but budget for eventual transmission work and avoid high-mileage neglected examples.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.