The 2002 GMT800 Yukon is a workhorse platform with rock-solid front suspension and frame, but it's plagued by transmission failures, intake manifold gasket leaks, and fuel system issues that can strand you. The 4.8L and 5.3L engines are generally reliable if the intake gaskets are addressed early; the 6.0L sees more bottom-end failures.
4L60E/4L65E Transmission Failure
Common · high severityTypical onset: 120,000-180,000 mi
Symptoms: harsh 1-2 shift or slipping in 2nd gear, delayed engagement into drive or reverse, transmission overheating, burnt fluid smell, check engine light with P0741 or P1870 codes
Fix: Rebuild or replace transmission. 3rd and 4th clutch packs burn up, torque converter fails. Rebuilt units last if the cooler lines are flushed and external cooler added. 8-12 labor hours for R&R plus rebuild time.
Estimated cost: $2,200-3,800
Intake Manifold Gasket Leak (Vortec V8s)
Common · medium severityTypical onset: 80,000-150,000 mi
Symptoms: coolant loss with no visible external leak, white smoke on cold start, rough idle or misfire codes, coolant in oil (milky dipstick) in severe cases
Fix: Replace plastic intake manifold gaskets with updated Fel-Pro composite set. Also inspect distributor O-ring. 4-6 labor hours. Critical to address before it causes bearing damage from coolant dilution.
Estimated cost: $600-1,200
Fuel Pump and Fuel Pressure Regulator Failure
Common · high severityTypical onset: 100,000-160,000 mi
Symptoms: hard starting, especially when hot, loss of power under load or uphill, stalling at idle after driving, strong fuel smell from tailpipe (regulator diaphragm leak)
Fix: Drop fuel tank to replace pump assembly and/or pressure regulator. Tank straps rust on northern vehicles, add time. Pump failure leaves you stranded. 3-5 labor hours depending on rust and 4WD skid plates.
Estimated cost: $650-1,100
ABS Module/Pump Failure and Brake Line Corrosion
Occasional · high severityTypical onset: 120,000+ mi
Symptoms: ABS light on with C0265 or C0241 codes, grinding/clicking from ABS pump on startup, spongy brake pedal, brake fluid leaks at rear brake hoses or steel lines at frame
Fix: ABS module rebuild or replacement ($400-800 part). Brake lines rot at frame brackets in rust belt. Full brake line replacement job is 6-8 hours. Module R&R is 2-3 hours, requires scan tool bleeding.
Estimated cost: $800-2,000
Instrument Cluster Stepper Motor Failure
Common · low severityTypical onset: 100,000-180,000 mi
Symptoms: speedometer, fuel gauge, or other gauges intermittent or dead, needles bouncing or stuck, no effect on driveability but annoying and fails inspection in some states
Fix: Remove cluster and replace individual stepper motors (solder job) or send to rebuild service. DIY-friendly if you can solder. 1-2 hours removal/reinstall, plus motor replacement time.
Estimated cost: $150-450
EVAP Vent Solenoid and Purge Valve Issues
Occasional · low severityTypical onset: 90,000-140,000 mi
Symptoms: check engine light P0440, P0446, P0455 EVAP codes, fuel smell near rear wheel well, difficulty filling gas tank (clicks off repeatedly)
Fix: Replace vent solenoid on top of fuel tank or purge valve near intake. Vent solenoid requires tank drop. 0.5 hour for purge valve, 3-4 hours for vent solenoid due to tank access.
Estimated cost: $200-700
Front Differential Fluid Leak and Axle Actuator Failure (4WD)
Occasional · medium severityTypical onset: 100,000+ mi
Symptoms: gear oil drips on garage floor from front diff, 4WD won't engage or service 4WD message, grinding or clunking when engaging 4WD, front axle actuator clicking but not engaging
Fix: Replace front diff seals or axle actuator. Actuator is thermal plastic, cracks over time. 2-3 hours for actuator, 3-4 hours for diff seal with axle shaft removal.
Estimated cost: $400-900
Exhaust Manifold Bolts Breaking and Manifold Cracks
Occasional · low severityTypical onset: 120,000+ mi
Symptoms: ticking/tapping noise on cold start, loudest first 30 seconds, exhaust leak smell in cabin with heater on, visible soot streaks on manifold
Fix: Extract broken bolts, install manifold with new gaskets and bolts. Passenger side is easy, driver side requires removal of steering shaft. 3-6 hours depending on side and bolt extraction difficulty.
Estimated cost: $500-1,200
Buy one if the transmission has been rebuilt and the intake gaskets replaced; pass if it has 150k+ on the original trans or shows coolant loss—otherwise a solid truck that's cheap to own.
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.