2007 GMC YUKON XL 2500

Typical onset: 80,000-150,000 mi

Symptoms: Ticking or tapping noise from engine, especially on cold start, Check engine light with P0300-series misfire codes or P0521 oil pressure, Loss of power under load, Metal shavings in oil, rapid oil consumption

Fix: AFM (Displacement on Demand) lifters collapse, wiping cam lobes and sending metal through the engine. Requires complete engine teardown: AFM lifter replacement, camshaft, all lifters, pushrods, sometimes rockers. In severe cases needs full shortblock with pistons, rings, bearings. 18-25 hours labor for shortblock R&R plus machine work.

Estimated cost: $4,500-8,500

Typical onset: 100,000-180,000 mi

Symptoms: Pink milkshake in coolant overflow tank (trans fluid in coolant), Transmission slipping or shuddering after coolant contamination, Low coolant level with no external leaks, Transmission overheating warnings

Fix: Factory crimped cooler lines inside radiator fail, allowing coolant and ATF to mix. Requires radiator replacement, cooler line set, full transmission flush or rebuild if contamination occurred. If caught early: 4-5 hours for radiator/lines/flush. If trans is damaged: add 12-16 hours for 4L80E rebuild.

Estimated cost: $800-1,200 (caught early), $3,200-4,800 (with trans rebuild)

Typical onset: 90,000-140,000 mi

Symptoms: No-start condition, cranks but won't fire, Intermittent stalling while driving, Check engine light with P0336 or P0335 codes, Tachometer drops to zero before stalling

Fix: Sensor located behind starter on bellhousing, exposed to heat. Requires starter removal for access. 1.5-2 hours labor.

Estimated cost: $250-400

Typical onset: 120,000-180,000 mi

Symptoms: Hard starting, extended cranking, Sputtering or hesitation under acceleration, Stalling when fuel level below 1/4 tank, Loss of power uphill or under load

Fix: In-tank pump assembly includes integral filter that cannot be serviced separately. Requires dropping 42-gallon tank. 2.5-3 hours labor.

Estimated cost: $650-950

Typical onset: 80,000-130,000 mi

Symptoms: Clunk when shifting from park to drive or reverse, Vibration at idle in gear, Excessive driveline movement visible during acceleration, Harsh engagement into gear

Fix: Rubber mount deteriorates, especially on tow-duty trucks. Replace mount and crossmember bushings. 1-1.5 hours labor.

Estimated cost: $220-380

Typical onset: 70,000-120,000 mi

Symptoms: Check engine light with P0449 or P0446 codes, Fuel tank pressure issues (hard to fill, vacuum hiss when opening cap), Failed emissions testing

Fix: Vent valve solenoid mounted on top of fuel tank fails due to corrosion or debris. Requires tank drop or working through frame access. 2-2.5 hours labor.

Estimated cost: $350-550