1971 PLYMOUTH DUSTER

Typical onset: 80,000-150,000 mi

Symptoms: Hard starting when warm, Rough idle with occasional backfiring, Rattling noise from front of engine on cold start, Check timing and it's retarded 8-12 degrees despite distributor being correct

Fix: Replace timing chain, gears, and front seal while you're in there. 4-6 hours labor for a V8. Must pull radiator, water pump, harmonic balancer, and timing cover. Replace oil pan gasket if it's seeping. Slant sixes (198/225) have timing chains but rarely stretch — if you have a six, this isn't your problem.

Estimated cost: $450-850

Symptoms: Clunking over bumps from front end, Wandering steering, car doesn't track straight, Uneven tire wear on inside edges, Visible rust-through on torsion bar crossmember, Car sits lower on one side

Fix: Lower control arm bushings are usually toast by now — original rubber turns to powder. Torsion bar sockets in the K-member rust from road salt. Plan 6-8 hours to do both sides properly: press out old bushings, install poly or rubber replacements, inspect/treat rust in crossmember pockets. If crossmember is rotted through, you're into welding or replacement K-member (major job). Alignment mandatory after.

Estimated cost: $600-1,200

Symptoms: Sudden no-start, cranks but won't fire, Stalling when hot, restarts when cool, Intermittent cutting out at highway speed, Burn marks or melted connector at ballast resistor

Fix: Factory 1971 came with points, but most have been converted to electronic (Mopar ECU or aftermarket). The ceramic ballast resistor on firewall cracks or the ECU box fails. Keep spares in glovebox — 15 minute roadside fix. If still on points, the rubbing block wears and point gap closes, causing weak spark and poor running. 1 hour to replace points, condenser, rotor, cap.

Estimated cost: $80-250

Symptoms: Hard starting, requires pumping accelerator, Hesitation or stumble on acceleration, Black smoke from exhaust, smells rich, Gas smell in garage, visible fuel weeping from carb base, Idle hangs high or hunts up and down

Fix: These run Carter BBD 2-barrel (slant six and 318) or Holley/Carter AFB 4-barrel (340/360). Ethanol fuel destroys old cork gaskets, accelerator pump diaphragms, and needle/seat assemblies. Full rebuild kit with proper non-ethanol-compatible parts: 3-4 hours for experienced tech, 6-8 if you've never done one. Consider replacement with remanufactured unit if body is heavily corroded. Adjustment and tuning adds 1 hour.

Estimated cost: $350-700

Symptoms: Visible holes in driver/passenger floor near seat mounts, Trunk spare tire well rusted through, Moisture inside car after rain, Carpet wet in rear seat footwells, Rear frame rail soft or flaking when poked

Fix: A-bodies trap moisture in front floor pans under carpet and rear quarters where trunk meets wheel wells. Minor surface rust is treatable; holes require patch panels or full floor replacement. Expect 12-20 hours labor for driver and passenger floors (cut out old, weld in new, seal, undercoat). Trunk floor: 8-12 hours. Frame rail replacement if compromised: major structural work, 20+ hours. This is welding-intensive — not a backyard bolt-on.

Estimated cost: $1,500-4,500

Symptoms: Sloppy shifter, hard to find gears, Grinding into second gear even with clutch fully depressed, Shifter pops out of third gear under load, Excessive side-to-side slop in shift lever

Fix: Linkage rods and plastic bushings wear out, allowing misalignment. Check shifter coupler at transmission — plastic insert cracks. Also inspect clutch adjustment; if clutch isn't releasing fully, you'll grind gears. Linkage rebuild: 2-3 hours, includes adjustment. If transmission itself is worn (synchros), you're into a pull and rebuild: 8-10 hours plus parts.

Estimated cost: $200-450 (linkage), $1,200-2,000 (trans rebuild)

Typical onset: 100,000+ mi

Symptoms: Gear oil puddle under rear of car, Oil spray on underside of trunk floor, Differential fluid low on dipstick check, Whining noise from rear end (if run low on fluid)

Fix: Pinion seal hardens and leaks. Pull driveshaft, remove pinion nut, press out old seal, install new one. Critical: mark pinion nut position or measure pinion bearing preload before removal — improper reassembly changes gear mesh and causes noise. 2-3 hours labor. If you've been driving it low on fluid, check for bearing damage (growling noise, loose pinion). Bearing replacement adds 4-6 hours.

Estimated cost: $250-500 (seal only), $600-1,000 (with bearings)