1984 JEEP CHEROKEE

Typical onset: 80,000-150,000 mi

Symptoms: rattling noise on cold startup that quiets as engine warms, rough idle and loss of power, check engine light or complete no-start if chain jumps timing, metal shavings in oil

Fix: The 2.8L GM-sourced V6 uses a timing chain that stretches and wears the nylon cam gear teeth. Replacement requires front cover removal, new chain, gears, and tensioner — about 6-8 hours labor. Often reveals additional wear requiring head gasket work or full teardown. Many shops won't touch these engines due to parts availability.

Estimated cost: $1,200-2,500

Symptoms: hard starting when cold or hot, stalling at idle or when coming to a stop, surging at highway speeds, black smoke from exhaust, fuel smell and poor mpg

Fix: The Carter BBD two-barrel carb is vacuum-sensitive and ethanol in modern fuel destroys gaskets and accelerator pump diaphragms. Rebuild kits run $40-80 but require 2-3 hours of careful work including float adjustment. Chronic cases need full replacement ($300-500 for remanufactured unit) or Weber conversion.

Estimated cost: $200-800

Typical onset: 100,000-150,000 mi

Symptoms: slipping between gears especially 1st to 2nd, delayed engagement when shifting to drive, transmission fluid that smells burnt or looks dark, whining or grinding noises, complete loss of forward gears

Fix: The Chrysler TorqueFlite 904 (called TH999 in Jeep applications) is light-duty for this truck and commonly fails from worn clutch packs and valve body issues. Rebuild takes 8-12 hours and requires specialized knowledge. Finding a quality rebuild shop that stocks parts is challenging. Transmission cooler lines rot out and cause overheating.

Estimated cost: $1,800-3,200

Typical onset: 120,000-200,000 mi

Symptoms: blue smoke on startup or acceleration, burning through a quart of oil every 500-1000 miles, fouled spark plugs, loss of power and poor fuel economy, failed emissions testing

Fix: Both the 2.5L and 2.8L suffer from worn rings and cylinder glazing at high mileage. Proper fix is engine rebuild with honing, new rings, and often pistons — 16-24 hours labor depending on condition. Many owners run heavier oil and add Lucas until the truck dies. Parts availability for the 2.8L makes rebuild economically questionable.

Estimated cost: $2,500-4,500

Symptoms: visible rust holes in rear floor under seats, soft spots when pressing on floor with foot, rust bubbling along rocker panels and rear wheel wells, sagging or misaligned doors, cracking sounds over bumps from weakened structure

Fix: The XJ unibody has no separate frame — the floor IS the structure. Road salt and water intrusion from old door seals destroy floor pans and rear cargo area. Proper repair requires cutting out rust and welding in new sheet metal (12-20 hours for extensive work). Rocker panel and wheel well replacement is common. Structural compromise affects safety.

Estimated cost: $1,500-5,000

Symptoms: rough idle that changes when revving, hissing sounds from engine bay, heater switching between vents randomly, transfer case won't engage properly, high idle or stalling

Fix: The 1984 Cherokee uses vacuum for emissions controls, HVAC blend doors, and 4WD engagement. 40-year-old vacuum lines become brittle and crack. Diagnosis takes 1-2 hours of tracing lines with a vacuum pump. Replacement lines are cheap but routing is complex. Often multiple leaks exist simultaneously.

Estimated cost: $150-400