The 2021 Tundra sits at the tail end of a platform that ran 2007-2021, meaning most design kinks were ironed out, but aged tech means it shares problems with older siblings. The 5.7L 3UR-FE is bulletproof when maintained, but several systemic issues persist.
Secondary Air Injection Pump Failure
Common · medium severityTypical onset: 60,000-100,000 mi
Symptoms: Check engine light with P0418/P0419/P2440 codes, Rough cold-start idle for first 30 seconds, Failed emissions testing
Fix: Replace air injection pump and/or combination valve assembly. 2-3 hours labor. Pumps seize from moisture ingress or simply wear out. Not a breakdown issue but kills emissions compliance.
Estimated cost: $800-1,400
Transmission Oil Cooler Line Corrosion
Common · high severityTypical onset: 70,000-120,000 mi
Symptoms: Transmission fluid leaking near radiator, Pink fluid puddles under front of truck, Low transmission fluid level triggering slipping or limp mode
Fix: Steel cooler lines rust through where they pass behind crossmember, especially in salt states. Replace both lines (they come as a pair). 3-4 hours labor plus fluid. Ignoring this grenades the transmission when it runs dry.
Estimated cost: $600-1,100
Exhaust Manifold Crack and Stud Failure
Occasional · medium severityTypical onset: 80,000-150,000 mi
Symptoms: Ticking noise from engine bay on cold start that fades as engine warms, Exhaust leak smell in cabin with heat on, P0420 catalyst efficiency code in some cases
Fix: Manifolds crack at the collector or studs break off in the head. Extraction of broken studs adds 2-4 hours. Full job: 6-8 hours for both banks if doing it right. OE manifolds will crack again; aftermarket headers solve it permanently but cost more.
Estimated cost: $1,800-3,200
Power Steering Rack Leaks
Occasional · medium severityTypical onset: 90,000-140,000 mi
Symptoms: Power steering fluid dripping from rack boots, Groaning or whining when turning at low speed, Steering wheel requires more effort when cold
Fix: Rack seals fail, often at inner tie rod boots. Rebuilding racks isn't cost-effective; most shops replace the entire unit. 4-5 hours labor plus alignment. There was a recall for faulty racks on some units, check VIN eligibility first.
Estimated cost: $1,200-2,000
Rear Driveshaft Carrier Bearing Failure
Occasional · medium severityTypical onset: 100,000-160,000 mi
Symptoms: Rumbling or droning noise from under cab at highway speeds, Vibration felt through floor at 55-70 mph, Noise changes with throttle application/deceleration
Fix: Two-piece driveshaft uses a center support bearing that wears out. Replace bearing and rubber mount. 2 hours labor. If ignored, imbalance can damage transmission output shaft seal or yoke.
Estimated cost: $400-700
Brake Master Cylinder Slow Internal Leak
Rare · high severityTypical onset: 120,000+ mi
Symptoms: Brake pedal slowly sinks to floor when holding steady pressure at stop, No external fluid leaks visible, Brakes work fine initially but pedal feels spongy over time
Fix: Internal seal bypass allows pressure to bleed down. Must replace master cylinder and bench-bleed before install. 2-3 hours including system bleed. Rare but dangerous when it happens.
Estimated cost: $500-850
Fuel Pump Assembly Failure (Rust-Belt Trucks)
Occasional · high severityTypical onset: 90,000-130,000 mi
Symptoms: No-start or intermittent stalling after sitting overnight, Check engine light with P0230 or P0231 codes, Fuel gauge erratic or stuck
Fix: Pump module corrodes internally from water intrusion via rusted tank seams or vent lines in salt states. Drop tank, replace entire assembly including sender and filter sock. 4-5 hours labor. California trucks rarely see this.
Estimated cost: $1,000-1,600
Buy it — the 2021 is the most refined version of a proven platform, and none of these issues are deal-breakers if you budget $1,500/year for maintenance beyond basics.
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.