2002 JEEP GRAND CHEROKEE

Typical onset: 80,000-140,000 mi

Symptoms: Harsh 2-3 shift or slipping in 3rd/4th gear under load, Transmission fluid milky/pink from coolant cross-contamination, Delayed engagement when cold, then complete loss of forward gears, Metal shavings in pan during routine service

Fix: Cooler lines crack or internal radiator trans cooler fails, pumping coolant into trans and destroying clutch packs. Requires transmission rebuild or replacement plus external cooler install, radiator replacement if internal cooler failed, and full fluid system flush. 12-16 labor hours for trans R&R and rebuild.

Estimated cost: $2,800-4,200

Typical onset: 100,000-160,000 mi

Symptoms: Coolant loss with no visible leaks, white smoke at startup, Misfires on specific cylinders (usually 6 or 8) that don't clear with plug/coil swaps, Overheating episodes followed by rough idle, Bubbles in coolant reservoir when engine running

Fix: Early PowerTech heads prone to cracking between valve seats, especially rear cylinders. Requires both head gaskets, machining or replacement heads, timing components, and complete cooling system refresh. 18-22 labor hours. Many shops recommend shortblock if bearings show wear during teardown.

Estimated cost: $3,500-5,800

Typical onset: 120,000-180,000 mi

Symptoms: Cold-start piston slap that lasts 30-60 seconds (distinct hollow knock), Low oil pressure at hot idle below 20psi, Rod knock on acceleration after engine fully warmed, Metal glitter or chunks in oil filter during changes

Fix: Inadequate piston-to-wall clearance from factory and thin bearing design leads to premature wear. Piston slap alone can persist 50k+ miles, but rod bearing failure is sudden. Full rebuild with oversized pistons and upgraded bearings, or shortblock replacement. 20-26 labor hours.

Estimated cost: $4,200-6,500

Typical onset: 90,000-150,000 mi

Symptoms: External coolant leak at back of head near firewall, Overheating with no visible radiator/hose leaks, Coolant smell in cabin, fogged windows, Cylinder 5 or 6 misfire with coolant in spark plug well

Fix: The 0331 casting (built 1999-2001, used through early 2002) cracks between cylinders 3-4 or near the coolant passages. Requires Tupy/newer 0331 replacement head or upgraded aftermarket casting, machining, and timing set. 10-13 labor hours. Verify casting number before purchase—Tupy castings rarely fail.

Estimated cost: $1,800-2,800

Typical onset: 70,000-110,000 mi

Symptoms: Clunking over bumps from front suspension, Steering wander and vague on-center feel, especially highway, Uneven inner tire wear on front tires, Visible torn rubber bushings at lower control arm pivot points

Fix: Factory rubber bushings deteriorate, causing alignment shift and poor handling. Replacement requires full lower control arms (bushings aren't serviceable separately in most shops). Alignment mandatory after. 3-4 labor hours both sides with alignment.

Estimated cost: $650-950

Typical onset: 120,000-170,000 mi

Symptoms: Grinding or rattling from under vehicle during acceleration, Binding or jerking in tight turns on dry pavement, Service 4WD warning light intermittent or constant, Vibration at highway speeds that worsens under load

Fix: NV247 transfer case chain stretches, and viscous coupler lockup causes binding. Requires case disassembly, chain and coupler replacement, and new fluid. Many shops recommend reman unit swap for labor efficiency. 6-8 hours for rebuild, 4-5 for swap.

Estimated cost: $1,400-2,200

Typical onset: 100,000-160,000 mi

Symptoms: Stalling or no-start when fuel tank below 1/4, Fuel gauge reading erratic or stuck at empty/full, Whining noise from rear during acceleration, Engine dies after 10-15 minutes running, restarts when cool

Fix: Fuel pump assembly fails from age and ethanol fuel degradation. Entire pump module with sending unit typically replaced as assembly. Tank drop required. 2.5-3 labor hours.

Estimated cost: $550-850