The 2004 Maxima's VQ35DE engine is generally bulletproof, but the RE4F04B automatic transmission is a ticking time bomb. The internal oil cooler fails catastrophically, mixing coolant and ATF—this single flaw defines ownership risk for the entire platform.
Transmission Radiator Internal Oil Cooler Failure (Strawberry Milkshake of Death)
Common · high severityTypical onset: 80,000-150,000 mi
Symptoms: Pink or milky transmission fluid—coolant mixing with ATF inside radiator, Transmission slipping, harsh shifts, or complete failure to engage gears, Overheating transmission temp gauge if owner catches it early, Engine overheating in advanced cases when ATF contaminates coolant system
Fix: Radiator replacement is only the start—if coolant entered the transmission, you need full trans flush minimum, often full rebuild or replacement (8-12 hours labor). Preventive fix: replace radiator and install external trans cooler before failure (3 hours).
Estimated cost: $400-800 preventive radiator/cooler install; $2,500-4,500 after failure with transmission rebuild
Transmission Control Module (TCM) Failure
Occasional · high severityTypical onset: 100,000-180,000 mi
Symptoms: Limp mode—stuck in 3rd gear only, won't shift, Check engine light with P1705 or P0705 shift position sensor codes, Intermittent no-start or transmission won't respond to gear selector, Harsh or delayed shifts before total failure
Fix: TCM is integrated into the valve body inside the transmission pan. Requires pan drop, valve body removal, TCM replacement, and relearn procedure (4-6 hours). Some shops rebuild the unit; most replace.
Estimated cost: $800-1,500
Engine Mount Failure (Especially Front/Transmission Mount)
Common · medium severityTypical onset: 70,000-120,000 mi
Symptoms: Excessive vibration at idle, especially in drive with brake on, Clunking when accelerating hard or shifting into reverse, Visible engine movement when revving in park, Steering wheel shake at idle that disappears at higher RPM
Fix: Front mount is hydraulic and fails most often. Right mount common too. Replace in pairs for best results—front and right typical (2-3 hours labor total).
Estimated cost: $350-600
Mass Airflow Sensor Contamination/Failure
Occasional · low severityTypical onset: 90,000-140,000 mi
Symptoms: Rough idle, stumbling on acceleration, Check engine light with P0171/P0174 lean codes or P0101 MAF range codes, Poor fuel economy, lack of power, Stalling at stop signs after extended highway driving
Fix: Try MAF sensor cleaner first (DIY 15 min). If that fails, replacement MAF (0.3 hours labor). Common on cars with oiled aftermarket air filters.
Estimated cost: $15 cleaner; $250-400 new sensor installed
Front Lower Control Arm Bushing Deterioration
Common · medium severityTypical onset: 80,000-130,000 mi
Symptoms: Clunking over bumps from front suspension, Steering wander, car tracks poorly on highway, Alignment won't hold—excessive/uneven front tire wear, Visible cracking or tearing in rubber bushings on inspection
Fix: Replace entire lower control arms with bushings pre-installed—pressing bushings separately is difficult and not cost-effective. Both sides recommended (2.5 hours). Alignment required after.
Estimated cost: $450-700 including alignment
Catalytic Converter Failure (Pre-Cat)
Occasional · medium severityTypical onset: 120,000-180,000 mi
Symptoms: Check engine light P0420/P0430 catalyst efficiency codes, Rattling from exhaust on cold start—substrate breaking apart internally, Slight power loss, reduced fuel economy, Sulfur smell from exhaust
Fix: Bank 1 and Bank 2 cats both common. OEM Nissan cats expensive; quality aftermarket (Magnaflow, Walker) acceptable. Both cats typically 3-4 hours labor.
Estimated cost: $800-1,400 for both banks with aftermarket cats
Crankshaft/Camshaft Position Sensor Failure
Occasional · high severityTypical onset: 100,000-160,000 mi
Symptoms: No-start or stalling while driving—often when engine is hot, Intermittent stalling at idle that restarts after cooling, Check engine light P0335 (crank sensor) or P0340 (cam sensor), Car dies suddenly on highway then restarts 20 minutes later
Fix: Crank sensor behind crankshaft pulley requires removal of accessories, belt, pulley (2 hours). Cam sensors on valve covers easier (0.8 hours each). Heat-related failures common—replace both crank and cam sensors preventively.
Estimated cost: $250-400 cam sensor; $300-500 crank sensor
Buy only if transmission radiator has been replaced with external cooler added—otherwise you're gambling $3,000+ on borrowed time; engine is stout but the trans issue is a deal-breaker without proof of preventive work.
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.