2001 CHEVROLET SILVERADO 2500HD

Typical onset: 100,000-200,000 mi

Symptoms: Hard starting, especially when cold, Excessive white smoke on startup, Fuel in crankcase oil (dilution), Rough idle and loss of power, Strong diesel smell from exhaust

Fix: LB7 injectors are under the valve covers—requires removing both covers, fuel rails, and all eight injectors. This is a 16-20 hour job. Injectors fail internally, leaking fuel into cylinders and oil. Always replace all eight at once with updated versions. Requires return line kit installation.

Estimated cost: $4,000-6,500

Typical onset: 80,000-150,000 mi

Symptoms: Transmission fluid leaking at radiator or lines, Transmission running hot (over 220°F), Pink milkshake in coolant reservoir (cooler rupture), Delayed or harsh shifting when hot

Fix: Factory cooler integrated into radiator fails internally or lines corrode at fittings. If coolant mixes with ATF, flush entire system immediately and replace radiator. External cooler upgrade highly recommended. Cooler line replacement is 2-3 hours, full radiator swap with flush is 4-6 hours.

Estimated cost: $800-2,200

Typical onset: 120,000-180,000 mi

Symptoms: Coolant loss with no external leaks, White smoke from tailpipe on cold start, Rough idle or misfire codes, Coolant smell in cab when heater runs, Oil contamination with coolant (milky dipstick)

Fix: Plastic intake manifold gaskets deteriorate and leak coolant into crankcase or intake ports. Requires upper intake manifold removal, gasket replacement, and thorough cleaning. 6.0L is 4-5 hours, 8.1L is 5-6 hours due to packaging. Use updated composite gaskets, not OEM plastic.

Estimated cost: $600-1,200

Typical onset: 150,000-220,000 mi

Symptoms: Slipping or flaring on 3-4 upshift, No fourth gear or overdrive, Burnt transmission fluid smell, Check engine light with P0734 code, Harsh 2-3 shifts as failure progresses

Fix: 4L80E transmissions behind gas engines wear out 3-4 clutch packs, especially in trucks used for towing. Requires full transmission rebuild or replacement. Rebuild is 8-12 hours, includes updated clutches, bands, and sonnax upgrades. Remanufactured units are cost-effective alternative.

Estimated cost: $2,200-3,800

Typical onset: 100,000-180,000 mi

Symptoms: Gear oil dripping from front wheel area, Grinding or humming noise from front end when in 4WD, Clunking when engaging four-wheel drive, Visible oil on inside of wheel rim

Fix: Front axle tube seals and unit bearings wear, especially on trucks in salt or heavy 4WD use. Requires hub removal, seal replacement, and bearing inspection. If bearing is damaged, full unit bearing replacement needed. 3-4 hours per side. Check both sides simultaneously.

Estimated cost: $400-900

Typical onset: 120,000-200,000 mi

Symptoms: No start or extended cranking, Engine dies while driving, Loss of power under load or acceleration, Whining noise from fuel tank, Low fuel pressure readings (under 55 psi gas, under 15,000 psi diesel)

Fix: Electric fuel pumps fail from age and contamination. Duramax has high-pressure CP3 pump on engine (8-10 hours with injector line work) plus lift pump in tank. Gas models have in-tank pump only (2-3 hours, must drop tank). Duramax CP3 failure often follows injector problems.

Estimated cost: $800-3,500

Typical onset: 80,000-140,000 mi

Symptoms: Clunking over bumps from front end, Wandering or loose steering feel, Uneven tire wear on inside edges, Steering wheel vibration, Failed inspection for excessive play

Fix: Heavy-duty use accelerates front suspension wear. Upper and lower ball joints plus inner/outer tie rods all wear together. Best practice is replacing all at once with heavy-duty Moog or equivalent parts. Requires alignment after. Full front end is 6-8 hours labor.

Estimated cost: $1,200-2,000