2006 GMC ENVOY

Typical onset: 80,000-150,000 mi

Symptoms: Pink or milky transmission fluid (coolant intrusion), Harsh or slipping shifts, delayed engagement, Transmission overheat warnings or limp mode, Complete transmission failure if coolant mixes with ATF

Fix: Requires replacement of radiator (internal trans cooler fails), all transmission fluid lines, complete fluid flush, and often transmission rebuild or replacement if contamination occurred. External trans cooler addition recommended. 10-16 hours labor for full job including trans R&R if rebuild needed.

Estimated cost: $2,800-5,500

Typical onset: 120,000-180,000 mi

Symptoms: Loud rattling noise on cold start that fades after 10-15 seconds, Check engine light with cam/crank correlation codes (P0016, P0017), Rough idle or misfires if severely stretched, Catastrophic engine damage if chain breaks or jumps timing

Fix: Front cover removal, timing chain kit replacement including guides, tensioner, and sprockets. Valve cover gaskets and front main seal typically done at same time. 8-12 hours labor depending on condition of seized bolts and corrosion.

Estimated cost: $1,800-3,200

Typical onset: 70,000-120,000 mi

Symptoms: Clunk when shifting from Park to Drive or Reverse, Vibration at idle especially when in gear, Visible engine/trans movement from outside when shifting, Excessive driveline lash when accelerating from stop

Fix: Replace transmission mount, often both front and rear mounts while in there. 1.5-2.5 hours labor with trans support required.

Estimated cost: $250-450

Typical onset: 60,000-100,000 mi

Symptoms: Clicking or ticking noise from behind dash, especially on startup or temp change, Air only blows hot or only blows cold regardless of setting, Temperature control works on one side but not the other (dual-zone), Grinding noise when adjusting temperature dial

Fix: Multiple actuators control different zones; driver side requires partial dash removal. 2-4 hours labor depending on which actuator(s) fail. Dorman replacements common but OEM lasts longer.

Estimated cost: $350-800

Typical onset: 80,000-140,000 mi

Symptoms: Service 4WD light illuminated on dash, Unable to engage or disengage 4WD modes, Grinding or clicking from transfer case area when trying to shift, Transfer case stuck in 4WD or 2WD

Fix: Replace encoder motor on transfer case. Sometimes just the contacts inside corrode and can be cleaned, but motor replacement is typical fix. 1.5-2 hours labor.

Estimated cost: $400-700

Typical onset: 100,000-160,000 mi

Symptoms: No-start condition, cranks but won't fire, Stalling at idle or under load, especially when fuel tank below 1/4, Loss of power under acceleration or on highway, Whining noise from rear/fuel tank area

Fix: Drop fuel tank, replace fuel pump module assembly. Fuel filter is integral to pump on this generation. 2.5-3.5 hours labor, more if tank straps are corroded.

Estimated cost: $600-1,100

Typical onset: 70,000-130,000 mi

Symptoms: Window falls into door or won't go up/down, Grinding or clicking noise when operating window switch, Window moves slowly or stops halfway, Backed by NHTSA recall on some units but many fail outside recall scope

Fix: Replace window regulator assembly, sometimes motor included. Rear doors require more disassembly. 1.5-2.5 hours per door.

Estimated cost: $300-550