1974 AMC HORNET

Typical onset: 80,000-130,000 mi

Symptoms: Delayed engagement or slipping between gears, especially 1-2 shift, Burnt transmission fluid smell, dark or metallic fluid on dipstick, Overheating in stop-and-go traffic or towing, loss of forward gears

Fix: Factory transmission cooler is inadequate; fluid breaks down fast. Requires external cooler installation (2 hours), fresh fluid/filter, or full rebuild if clutches are burnt (8-12 hours). Many need rebuilds before 100k if cooler wasn't added early.

Estimated cost: $400-700 for cooler/service, $1,800-2,800 for rebuild

Symptoms: Visible rust-through behind rear wheels at rocker/floor junction, Rear leaf spring mounts separating or pulling through weakened metal, Clunking from rear suspension under load, body flex or squeaks

Fix: The rear torque boxes and inner rockers rot from inside out—salt and mud pack in there. Proper repair means cutting out rust, welding in patch panels or full torque box sections (12-20 hours depending on severity). Cosmetic bondo over rust fails fast.

Estimated cost: $1,500-3,500 depending on extent

Typical onset: 60,000-110,000 mi

Symptoms: Loud ticking or popping noise from engine bay that increases with RPM, Exhaust smell in cabin with heater on, Visible cracks between ports 3-4 or at mounting bolt bosses

Fix: AMC I6 manifolds crack due to thermal cycling and poor casting quality. Replacement requires removing air cleaner, carb linkage, exhaust pipe (often seized hardware), and manifold (3-5 hours). Used manifolds often cracked too; consider headers if available.

Estimated cost: $400-750

Typical onset: 70,000+ mi or 5+ years sitting

Symptoms: Hard starting when cold, requires multiple pumps or cranking, Hesitation or stumble on acceleration from stop, Fuel smell or wet spark plugs, flooding if float sticks

Fix: Ethanol fuel eats the original cork float and rubber accelerator pump. Rebuild with modern ethanol-compatible kit (2-3 hours including removal, cleaning, reinstall, and adjustment). These carbs are simple but require patience to set float level and pump stroke correctly.

Estimated cost: $250-450

Typical onset: 90,000-150,000 mi

Symptoms: Oil drips or puddle under bellhousing area after sitting, Oily residue coating clutch or flywheel (manual), torque converter area (auto), Oil consumption without visible leaks up top

Fix: AMC I6 uses a two-piece rear main seal that hardens and leaks over time. Requires transmission removal (4-6 hours manual, 6-8 hours auto). Rope seal installation is finicky; too tight causes crankshaft drag, too loose still leaks. Replace both halves and side seals while in there.

Estimated cost: $600-1,200

Typical onset: 70,000-120,000 mi

Symptoms: Clunking over bumps or when turning at low speed, Excessive play in wheel when jacked up, tire can be rocked top-to-bottom, Wandering steering or uneven tire wear on inside edge

Fix: Upper and lower ball joints wear, especially if grease fittings weren't maintained. Lower ball joint failure can cause wheel separation. Both uppers and lowers should be replaced together (4-6 hours), requires pressing or ball joint tool. Alignment mandatory after.

Estimated cost: $500-900

Symptoms: Fuel gauge reads empty, full, or erratic regardless of actual level, Rust flakes in fuel filter, clogged filter repeatedly, Running issues after sitting—picks up sediment when tank gets low

Fix: Steel fuel tanks rust internally, especially if the car sat or ran on small amounts of fuel. Sending unit float arm corrodes or gets stuck. Drop tank (2-3 hours), inspect for rust pinholes. Clean and seal if surface rust only, or replace tank and sender unit together.

Estimated cost: $400-800