1979 PONTIAC FIREBIRD

Typical onset: 80,000-140,000 mi

Symptoms: Slipping between gears, especially 2nd to 3rd, Delayed engagement when shifting into drive or reverse, Burnt transmission fluid smell and dark fluid color, Hard shifting or no upshift under load

Fix: Rebuild required in most cases. TH350 units typically fail due to worn clutch packs and seals. Expect 12-16 hours for R&R and rebuild, plus new torque converter recommended. External cooler lines often leak at radiator connections—inspect during any trans work.

Estimated cost: $1,800-3,200

Typical onset: 100,000-150,000 mi

Symptoms: Heavy knocking from crankcase, worsens with RPM, Loss of oil pressure, especially at idle, Metal shavings in oil during changes, Sudden catastrophic failure with rod through block

Fix: The 301 Pontiac and 305 Chevy engines suffer from weak bottom ends—main and rod bearings wear prematurely, especially if oil changes were neglected. Requires complete short block replacement or full rebuild with crank machining. Plan 24-32 hours labor for engine pull, machine work, and reinstall.

Estimated cost: $3,500-6,000

Symptoms: Rough idle, surging at cruise, Black smoke from exhaust under acceleration, Stalling when coming to a stop, Hard starting when warm, flooding, Poor fuel economy—single digits in V8 applications

Fix: The Quadrajet carbs on these cars are 45+ years old now—accelerator pump seals, float needles, and power piston assemblies deteriorate. Ethanol fuel accelerates internal component degradation. Full rebuild with quality kit takes 4-6 hours including removal, bench work, and tuning. Many opt for replacement with remanufactured unit.

Estimated cost: $450-900

Typical onset: 60,000-100,000 mi

Symptoms: Gear oil spots on garage floor near rear wheels, Visible oil coating on inside of wheel or brake drum, Whining or howling from rear end under load, Low differential fluid level on inspection

Fix: The 10-bolt and 12-bolt rear ends in these cars commonly leak from axle seals and pinion seals. Axle seals are straightforward—2 hours per side including draining fluid. Pinion seals require driveshaft removal and careful crush sleeve setup—4-5 hours. If differential is whining, bearing replacement adds significant cost.

Estimated cost: $300-700

Symptoms: Visible rust perforation in floor pans behind seats, Soft or crumbling metal at rear torque box areas, Front subframe rust near control arm mounts, Fuel tank strap failure due to corrosion, Water intrusion into cabin during rain

Fix: This is the killer for F-bodies from rust belt states. Floor pans, torque boxes, and front subframe rails rot out from trapped moisture. Proper repair requires full media blasting, cut-and-weld patch panels or replacement sections. Quality restoration-level work runs 40-80 hours depending on extent. Subframe replacement alone is 16-20 hours.

Estimated cost: $4,000-12,000

Typical onset: 70,000-120,000 mi

Symptoms: Power steering fluid leaking from gearbox or lines, Excessive play in steering wheel—2+ inches before response, Wandering on highway, constant correction needed, Groaning noise when turning at low speed

Fix: Saginaw manual and power steering boxes develop internal wear and seal leaks. Adjustment can take up some slop temporarily (1 hour), but most need rebuild or replacement. Gearbox R&R is 3-4 hours, rebuilt units recommended over used. Check pitman arm and idler arm simultaneously—commonly worn.

Estimated cost: $600-1,200

Symptoms: Fuel gauge reads empty regardless of fill level, Erratic gauge movement or stuck at full, Fuel smell in cabin or trunk area, Visible rust or pinholes on external tank surface, Fuel pump pickup screen clogged with rust debris

Fix: Steel fuel tanks rust from inside out, especially with ethanol fuel and moisture. Sending unit float arms corrode and break. Tank removal requires 4-5 hours (exhaust, straps, filler neck, all lines). New tank plus sending unit recommended—used tanks are equally old. If keeping original tank, professional cleaning and sealing adds 2-3 hours.

Estimated cost: $800-1,400