2007 CHEVROLET TRAILBLAZER SS

Typical onset: 80,000-150,000 mi

Symptoms: Ticking/tapping noise from engine on cold start that may disappear when warm, Check engine light with P0300-series misfire codes or P0521 oil pressure, Loss of power, rough idle, fuel economy drop, Metal shavings in oil, collapsed lifter destroys camshaft lobes and pushrod

Fix: AFM system failure requires camshaft replacement, lifters, pushrods, and often machine work on cylinder heads. Many owners opt for AFM delete kit during repair. Budget 18-25 labor hours for proper repair with head work. Neglected cases result in complete engine rebuild or replacement when metal contaminates bearings.

Estimated cost: $3,500-6,500

Typical onset: 90,000-140,000 mi

Symptoms: Harsh 1-2 or 2-3 shifts, slipping under acceleration, Shuddering during light throttle cruise around 40-50 mph, Transmission fluid discolored or burnt smell, Delayed engagement when shifting into drive or reverse

Fix: The 4L65E behind the 395hp LS2 is undertorqued and wears clutch packs, particularly 3-4 clutches. Internal oil cooler line failures also contaminate fluid. Rebuild requires 10-14 hours; many shops recommend performance rebuild with upgraded clutches and shift kit for longevity. External cooler line leaks can contaminate coolant requiring radiator replacement as well.

Estimated cost: $2,800-4,200

Typical onset: 70,000-120,000 mi

Symptoms: Pink or milky transmission fluid (coolant contamination), Transmission slipping or erratic shifting after fluid turns milky, Engine overheating or sweet smell from exhaust, Rapid transmission failure after cross-contamination begins

Fix: The internal transmission cooler inside the radiator develops leaks, allowing coolant and ATF to mix. Requires radiator replacement, full transmission fluid flush (often multiple flushes), and external auxiliary cooler installation. If caught early (within days), transmission may survive; delayed response means full rebuild. 4-6 hours labor for radiator and cooler, plus transmission service or rebuild.

Estimated cost: $800-1,200 (caught early), $3,500-5,000 (with transmission rebuild)

Typical onset: 90,000-130,000 mi

Symptoms: Service 4WD light illuminated on dash, Grinding or humming noise from front differential during acceleration, 4WD system won't engage or engages randomly, Clunking when turning if carrier bearings worn

Fix: The electronic front axle actuator fails, leaving vehicle in 2WD. Carrier bearings also wear on AWD models due to constant engagement. Actuator replacement is 2-3 hours; carrier bearing service requires differential teardown at 5-7 hours. Many owners upgrade to manual locking hubs to eliminate actuator issues.

Estimated cost: $600-900 (actuator), $1,200-1,800 (carrier bearings)

Typical onset: 80,000-110,000 mi

Symptoms: Clunking noise from rear over bumps or during acceleration/braking, Rear end feels loose or wanders on highway, Uneven rear tire wear, Visible cracking or separation of rubber bushings on control arms

Fix: The rear upper and lower control arm bushings deteriorate, causing handling slop and alignment issues. The SS's performance tires accelerate wear. Complete rear control arm replacement recommended over bushing-only jobs due to labor overlap. 4-6 hours for all four arms plus alignment.

Estimated cost: $1,200-1,800

Typical onset: 100,000-150,000 mi

Symptoms: Hard starting or extended cranking, especially when hot, Loss of power under heavy acceleration or uphill, Engine sputtering or hesitation at highway speeds, Check engine light with lean fuel codes (P0171/P0174)

Fix: In-tank fuel pump strainers clog with sediment, starving the thirsty LS2. The inline fuel filter (frame-mounted) also restricts flow. Pump replacement requires tank drop at 3-4 hours; filter alone is 0.5-1 hour but often done together. Ethanol fuel exacerbates debris buildup in these aging tanks.

Estimated cost: $450-650 (filter), $800-1,200 (pump assembly)