2005 INFINITI FX35

Typical onset: 60,000-120,000 mi

Symptoms: Sudden loss of 5th gear or limp mode with no prior warning, Metallic debris in fluid, radiator coolant mixing with ATF via internal cooler failure, Transmission slipping, delayed engagement, or complete loss of forward gears, Check engine light with speed sensor or ratio codes

Fix: This is the killer issue. The transmission cooler inside the radiator fails, allowing coolant and ATF to mix, destroying clutch packs and valve body. Requires radiator replacement, full transmission rebuild or replacement, and complete fluid flush of cooling system. 12-16 hours labor for transmission R&R plus rebuild.

Estimated cost: $3,500-5,500

Typical onset: 80,000-150,000 mi

Symptoms: Burning 1+ quart of oil every 500-1,000 miles with no external leaks, Blue smoke on cold start or acceleration, Fouled spark plugs, misfires on multiple cylinders, Engine knock or failure if oil level drops unnoticed

Fix: Pre-cat failure dumps material into cylinders, scoring bores and destroying piston rings. Also carbon buildup on ring lands from direct oil burning. Requires engine teardown, cylinder honing or re-sleeving, new pistons and rings. Many shops recommend short block replacement or used engine due to labor cost. 20-28 hours for engine removal and internal rebuild.

Estimated cost: $4,500-7,500

Typical onset: 70,000-130,000 mi

Symptoms: Fluid dripping from center of vehicle underside, Clunking when shifting from Park to Drive, Vibration at highway speeds that feels like driveline lash, Binding or jerking in tight turns (AWD system fighting itself)

Fix: Front transfer case seal leaks, and the shared transmission/transfer case mount deteriorates. Seal replacement requires transmission drop in most cases. Mount is 2-3 hours standalone. Often done together. Fluid leak can starve transfer case and destroy it if ignored.

Estimated cost: $800-1,800

Typical onset: 60,000-100,000 mi

Symptoms: Clunking over bumps from front suspension, Steering feels vague or wanders on highway, Uneven inner tire wear, Alignment won't hold or camber out of spec

Fix: The front LCA rear bushings tear and separate. Infiniti sells only complete control arms, not bushings separately. Both sides typically need replacement. 3-4 hours for both sides including alignment.

Estimated cost: $800-1,200

Typical onset: 80,000-140,000 mi

Symptoms: Gear oil dripping from front of rear differential, Whining or howling from rear end under acceleration, Low fluid causes bearing damage and catastrophic failure

Fix: Pinion seal fails, and owners don't notice until fluid is critically low. Requires driveshaft removal, pinion nut torque spec is critical (crush sleeve setup). If caught early, 2-3 hours. If bearings are damaged, differential rebuild adds 6-8 hours.

Estimated cost: $400-2,200

Typical onset: 90,000-150,000 mi

Symptoms: Rough idle, hesitation, or poor throttle response, Check engine light with lean or rich fuel trim codes, Stalling at idle after deceleration, Poor fuel economy (2-4 MPG drop)

Fix: VQ35DE uses hot-wire MAF sensors that get contaminated from oil vapor (see oil consumption issue). Cleaning rarely works long-term. Genuine Nissan sensor required; aftermarket units cause issues. 0.5 hours labor, but part is expensive.

Estimated cost: $350-550