2016 CHEVROLET SILVERADO 2500HD

Typical onset: 150,000-250,000 mi

Symptoms: excessive blowby from crankcase, white or blue smoke on cold starts, loss of compression in one or more cylinders, metallic knocking or rattling, fuel dilution in oil

Fix: The LML is prone to cracked pistons, especially in tuned or hard-worked trucks. Once diagnosed, it's either a short block replacement (25-35 hours) or full engine rebuild with upgraded pistons. Many shops recommend forged piston upgrades at this point to prevent recurrence.

Estimated cost: $8,000-15,000

Typical onset: 80,000-150,000 mi

Symptoms: transmission fluid leaking near radiator, pink fluid puddles under truck, transmission overheating warnings, milky transmission fluid (indicates coolant cross-contamination)

Fix: The cooler lines corrode where they connect to the radiator or at compression fittings. If coolant mixes with ATF, the transmission is toast—flush immediately if caught early. Line replacement is 2-3 hours; if the trans is contaminated, add another 8-12 hours for a rebuild or replacement.

Estimated cost: $300-600 (lines only), $3,500-5,500 (if transmission damaged)

Typical onset: 100,000-180,000 mi

Symptoms: sudden loss of power and no-start, metal shavings in fuel filter, rough running and misfires, fuel system codes (P0087, P0093), entire fuel system contaminated with metal debris

Fix: The CP4.2 pump grenades internally, sending metal through the entire fuel system. This requires replacing the pump, all injectors, fuel rails, lines, filter housing, and flushing the tank—a nightmare job at 20-30 hours. Some owners install CP3 conversion kits or aftermarket filtration as preventive measures.

Estimated cost: $8,000-12,000

Typical onset: 70,000-120,000 mi

Symptoms: shudder or vibration during light acceleration at 30-50 mph, delayed or harsh shifts, slipping between gears, transmission overheating

Fix: The Allison can develop torque converter clutch shudder, often fixable with a fluid and filter change using fresh Dexron VI (2 hours). If that doesn't solve it, the converter itself is failing—requires transmission removal and rebuild at 12-16 hours. Don't ignore this; it leads to full transmission failure.

Estimated cost: $300-500 (fluid service), $3,000-4,500 (converter replacement)

Typical onset: 100,000-150,000 mi

Symptoms: 'DEF system fault' warnings, reduced engine power mode, DEF gauge reading incorrectly, crystallized DEF in tank or lines, won't start or speed limited to 5 mph

Fix: DEF quality and cold weather cause heater failures, level sensor issues, and injector clogging. Individual sensor or heater replacements run 2-4 hours. If the entire DEF tank assembly is contaminated, it's 6-8 hours to drop and replace everything. Always use fresh DEF and keep the tank above 1/4 in winter.

Estimated cost: $400-1,200 (sensors/heaters), $1,500-2,500 (full tank assembly)

Typical onset: 60,000-100,000 mi

Symptoms: clunk when shifting into drive or reverse, vibration at idle in gear, excessive driveline movement, visible cracks or separation in rubber mount

Fix: The rubber transmission crossmember mount fatigues and tears, especially in trucks that tow heavy. Replacement is straightforward at 1-1.5 hours with a transmission jack to support the tailhousing. Cheap insurance to prevent driveline damage.

Estimated cost: $200-400