1972 BUICK GS

Typical onset: 80,000-150,000 mi

Symptoms: Slipping between gears, especially 2nd to 3rd, Delayed engagement when shifting into Drive or Reverse, Burnt transmission fluid smell, dark or metallic fluid, Hard shifts or no upshift under load

Fix: Full rebuild with clutch packs, bands, seals, and filter; 8-12 labor hours depending on condition. Torque converter often needs replacement. Transmission mounts typically replaced during R&R.

Estimated cost: $2,200-3,800

Typical onset: 100,000-180,000 mi

Symptoms: Low oil pressure at idle (under 10 psi hot), Knocking or ticking from lower engine, worse on cold start, Metal shavings in oil or on drain plug magnet, Oil consumption increase without visible leaks

Fix: Requires engine removal, crankshaft inspection/machining, new bearings (mains and rods), often pistons and rings if bore is worn. 20-30 labor hours for full teardown and reassembly. 455s see this more often due to larger bearing surfaces and higher stress.

Estimated cost: $4,500-7,500

Symptoms: Hard starting after sitting, especially hot restart, Rough idle or stumbling under acceleration, Fuel smell in cabin or garage, Visible corrosion in fuel tank or lines

Fix: Modern ethanol fuel attacks original rubber hoses, fuel pump diaphragms, and tank linings. Replace all rubber fuel lines, fuel filter, fuel pump, and inspect/clean or replace tank. Add inline filter. 4-6 hours labor if tank removal needed.

Estimated cost: $600-1,400

Typical onset: 120,000-200,000 mi

Symptoms: Blue smoke on startup or deceleration, High oil consumption (1 qt per 500-800 miles), Loss of compression, poor performance, Excessive blowby into PCV system

Fix: Requires cylinder honing or boring oversized, new piston rings or complete piston set. Usually combined with bearing work. 18-25 labor hours if engine stays in car (deck plate hone), otherwise full removal. 350 usually cheaper than 455 due to parts availability.

Estimated cost: $2,800-5,200

Symptoms: Transmission fluid leak under front of car near radiator, Transmission overheating, burnt fluid smell, Loss of fluid leading to slipping or no engagement

Fix: Steel cooler lines rust through at bends or connections, especially in rust-belt cars. Replace both lines as a pair with proper double-flare fittings. 2-3 hours labor. Also flush external cooler if equipped.

Estimated cost: $300-550

Typical onset: 60,000-100,000 mi

Symptoms: Excessive engine movement on acceleration or deceleration, Clunking when shifting into gear, Vibration felt through floor or steering wheel, Visible cracking or separation of rubber mount material

Fix: Rubber mounts harden and crack over decades. Replace engine mounts (both sides) and transmission mount as a set. 2-4 hours labor total. Required for proper driveline alignment and to prevent accessory damage.

Estimated cost: $400-750