2023 GMC SIERRA 2500HD

Typical onset: 30,000-80,000 mi

Symptoms: sudden loss of power, white smoke from exhaust, hard starting or no-start, metal shavings in fuel system, fuel rail pressure codes (P0087, P1093)

Fix: When the CP4.2 pump grenades, metal contamination spreads through the entire fuel system. Requires complete fuel system flush, new injectors (all 8), fuel lines, fuel rails, lift pump, and high-pressure pump. 18-24 hours labor depending on contamination severity. Aftermarket CP3 conversion kits available for $3,000-4,000 as preventive measure.

Estimated cost: $8,000-15,000

Typical onset: 20,000-60,000 mi

Symptoms: knocking noise from lower engine, loss of oil pressure, metal shavings in oil, sudden catastrophic failure while towing, check engine light with misfire codes

Fix: Primarily seen in trucks used for heavy towing or sustained high load. Pistons crack or bearings spin, requiring complete engine rebuild or short block replacement. GM has issued some goodwill coverage case-by-case. 22-30 hours labor for short block swap, more for full teardown and rebuild.

Estimated cost: $12,000-18,000

Typical onset: 40,000-90,000 mi

Symptoms: transmission fluid puddle under truck, fluid level dropping, transmission running hotter than normal, burnt smell from fluid

Fix: External cooler lines or cooler itself develop leaks at fittings. Often caught early during service. Cooler replacement requires dropping exhaust and disconnecting lines. 4-6 hours labor. Sometimes just line replacement if caught early.

Estimated cost: $800-1,800

Typical onset: 50,000-100,000 mi

Symptoms: DEF warning lights, reduced engine power message, DEF gauge reading empty when full, truck won't start after sitting in cold weather, P20EE, P204F codes

Fix: DEF tank heater element or level sender fails, especially in cold climates. Tank must be drained and removed for sender replacement. Heater can sometimes be replaced separately. 3-5 hours labor depending on component.

Estimated cost: $600-1,400

Typical onset: 60,000-120,000 mi

Symptoms: clunk when shifting into drive or reverse, vibration under acceleration, driveline shudder especially when towing, visible sagging or torn rubber on mount

Fix: Rear transmission mount rubber separates or crushes under heavy use. Simple replacement but requires supporting transmission. 1.5-2.5 hours labor.

Estimated cost: $300-600

Symptoms: diesel smell around engine bay, visible fuel leak at filter housing, hard starting in cold weather, air in fuel system codes

Fix: Filter head o-rings and water-in-fuel sensor seals leak over time, accelerated by poor fuel quality or extended filter intervals. Housing replacement or reseal needed. 2-3 hours labor including priming system.

Estimated cost: $400-900