The 1975 Skylark rides on GM's A-body platform with carburetor engines choked by early emissions controls. Biggest headaches are TH350 transmission failures, carburetor issues from ethanol fuel, and engine rebuilds driven by weak piston rings and worn main bearings—often cheaper to swap than rebuild.
TH350 Transmission Failure (Slipping, No Reverse)
Common · high severityTypical onset: 80,000-130,000 mi
Symptoms: Slipping between gears especially 1-2 shift, Loss of reverse or delayed engagement, Brown or burnt transmission fluid, Whining noise in gear
Fix: Rebuild or replace TH350. Inspect torque converter for debris. Often find worn clutch packs and hardened seals. Rebuild takes 8-12 labor hours including R&R, fluid, and filter. Many opt for remanufactured unit to save time.
Estimated cost: $1,200-2,400
Worn Piston Rings and Oil Consumption
Common · medium severityTypical onset: 90,000-150,000 mi
Symptoms: Blue smoke on startup or acceleration, Burning 1+ quart oil every 500-800 miles, Fouled spark plugs, Loss of compression in one or more cylinders
Fix: Requires engine teardown for ring replacement. If bores are scored, needs overbore and oversized pistons. Most techs recommend full rebuild at this point since you're already in there—new main bearings, rod bearings, cam, timing set. 20-30 hours for full rebuild.
Estimated cost: $2,800-4,500
Rochester Carburetor Flooding and Stalling
Common · medium severitySymptoms: Hard starting when hot, Stalling at idle or when coming to stops, Raw fuel smell, gas dripping from carb, Black smoke and poor fuel economy
Fix: Rochester 2-barrel carbs don't tolerate ethanol well—needle/seat wears, float sinks, accelerator pump diaphragm cracks. Rebuild kit with ethanol-resistant parts plus carb cleaning runs 3-5 hours. If base is warped or stripped, replacement needed.
Estimated cost: $350-750
Main Bearing Wear and Crankshaft Damage
Occasional · high severityTypical onset: 120,000-180,000 mi
Symptoms: Deep knocking sound from bottom end, worse under load, Low oil pressure at idle (under 10 psi), Metallic debris in oil or filter, Engine vibration
Fix: Requires crankshaft removal, inspection, and likely machine work (grinding undersize if journals scored). If crank is toast, sourcing replacement for 260 V8 can be tough—350 parts more available. Full bottom-end rebuild, 18-25 hours. Often more cost-effective to swap in running used engine.
Estimated cost: $2,500-4,200
Deteriorated Transmission Mount
Common · low severityTypical onset: 60,000-100,000 mi
Symptoms: Clunk when shifting from park to drive/reverse, Vibration at idle in gear, Visible sagging of transmission tailshaft, Harsh engagement
Fix: Rubber transmission mount collapses over time. Replace mount and inspect crossmember for cracks. Simple job: 1-1.5 hours to drop crossmember and swap mount.
Estimated cost: $120-250
Leaking Transmission Oil Cooler Lines
Occasional · medium severitySymptoms: ATF puddles under front of car, Low transmission fluid without visible leak at pan, Transmission overheating, Fluid sprayed on undercarriage
Fix: Steel lines rust through where they connect to radiator or at fittings. Replace both lines as a pair—originals are 50 years old. Pre-bent replacements available, 2-3 hours to install and refill system.
Estimated cost: $200-400
Buy only if you're handy or have a cheap engine/trans source—these need major drivetrain work within 20k miles of purchase, and parts scarcity on the 260 V8 makes the 350-equipped cars the smarter pick.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.