2006 CHEVROLET IMPALA SS

Typical onset: 80,000-140,000 mi

Symptoms: Sudden loss of power, heavy blue smoke, and oil consumption over 1 qt/500 mi, Rod knock or deep bottom-end knocking on cold start, Metal shavings in oil, check engine light with misfire codes, Catastrophic failure: connecting rod through block

Fix: The LS4 suffers from piston ring land failures and bearing wear, especially in engines that saw hard launches or poor oil change intervals. Repair requires full engine rebuild or short block replacement—typically 18-24 labor hours for R&R plus machine work. Many owners opt for used engine swaps due to cost.

Estimated cost: $4,500-8,000

Typical onset: 90,000-130,000 mi

Symptoms: Harsh 2-3 shift or slipping under throttle, Transmission shudder on acceleration, Delayed engagement into drive or reverse, Complete loss of forward gears, stuck in 2nd or 3rd

Fix: The 4T65E-HD was beefed up for the SS but still struggles with 303 lb-ft of torque. Input shaft splines strip, clutch packs burn, and the differential can grenade. Full rebuild takes 12-16 hours; many shops won't rebuild them anymore and go straight to reman unit.

Estimated cost: $3,200-4,800

Typical onset: 70,000-110,000 mi

Symptoms: Pink or milky transmission fluid (coolant contamination), Overheating transmission, burnt smell, Strawberry milkshake appearance in coolant reservoir, Transmission slipping after coolant intrusion

Fix: The internal trans cooler in the radiator fails, mixing coolant and ATF—kills the transmission in days if not caught. Requires new radiator, external trans cooler install, full fluid flush (multiple times), and often transmission rebuild if driven after contamination. Radiator replacement alone: 3-4 hours.

Estimated cost: $800-1,200 (preventive radiator/cooler), $4,000-6,500 (if trans damaged)

Typical onset: 100,000-150,000 mi

Symptoms: White smoke from exhaust, sweet smell, Coolant loss with no visible leaks, Overheating, especially under load, Bubbles in coolant reservoir when running

Fix: LS4 head gaskets can fail, especially if the engine overheated previously or had coolant neglect. Both heads typically need resurfacing. Labor-intensive due to FWD packaging—must pull intake, exhaust manifolds, accessories. 14-18 hours labor, plus machine work if heads are warped.

Estimated cost: $2,800-4,200

Typical onset: 60,000-100,000 mi

Symptoms: Severe clunk on hard acceleration or deceleration, Excessive engine/trans movement visible under hood, Vibration at idle in gear, Difficulty shifting into gear

Fix: The torque from the LS4 destroys the upper transmission mount quickly. Collapsed mount allows excessive powertrain movement, which accelerates CV axle and transmission damage. Replacement is 2-3 hours—must support trans and engine properly. Use OEM or polyurethane aftermarket.

Estimated cost: $250-450

Typical onset: 80,000-120,000 mi

Symptoms: Hard starting, especially when hot, Loss of power under load, hesitation, Fuel pressure drop, check engine light for lean codes, Whining noise from rear of vehicle

Fix: Fuel pump failures send debris through the system; if the inline filter wasn't serviced (many techs overlook it), contamination reaches injectors. Pump replacement: 2-3 hours (drop tank). Filter change: 0.5 hours but requires lifting vehicle. Injector cleaning/replacement adds cost if contaminated.

Estimated cost: $600-900 (pump/filter), $1,200-1,800 (if injectors involved)