1977 BUICK SKYLARK

Typical onset: 60,000-90,000 mi

Symptoms: Slipping between 1st and 2nd gear under load, No reverse or delayed engagement, Metal shavings in pan during fluid change, Shuddering or flaring during upshifts

Fix: The THM 200 (metric 200) was GM's economy transmission and notoriously weak behind even the anemic 231 V6. Rebuild requires 8-12 hours with hardened input shaft, better clutches, and upgraded bands. Many shops recommend swapping to a THM 350 instead for longevity (requires crossmember modification and driveshaft work, adding 4-6 hours).

Estimated cost: $1,800-3,200

Typical onset: 80,000-130,000 mi

Symptoms: Deep knocking sound from bottom end, especially when cold, Low oil pressure at idle (below 10 psi), Metallic debris in oil filter, Sudden catastrophic failure with rod through block

Fix: The Buick 231 odd-fire V6 has weak main bearing journals and inadequate oiling to #1 and #4 mains. Low oil pressure accelerates wear. Requires complete teardown with crank grinding or replacement, new mains, and sometimes block align-honing. Figure 18-24 hours for proper repair. Many techs recommend upgrading to the even-fire 231 crank if available or swapping to a small-block V8.

Estimated cost: $2,500-4,500

Symptoms: Rust bubbling behind rear wheels and lower quarters, Rocker panel deterioration with holes visible, Trunk floor rust-through near wheel wells, Frame surface rust progressing to structural weakness at body mounts

Fix: A-body quarter panels and rockers rust from the inside out due to poor drainage and no factory rust protection. Quarter panel replacement requires 12-16 hours per side with proper metalwork. Frame rust at body mount points can compromise structural integrity—inspect carefully before purchase. Patch jobs rarely last more than 2-3 years in rust belt climates.

Estimated cost: $1,500-3,500

Typical onset: 50,000-100,000 mi

Symptoms: Hard starting when hot or cold, Rough idle and stalling at stop lights, Black smoke and fuel smell from exhaust, Hesitation on acceleration

Fix: The Rochester 2GC and 2GE carburetors used in '77 are clogged with emission controls and vacuum lines that crack with age. Full rebuild with new vacuum hoses, EGR valve, and choke adjustment takes 3-5 hours. Many owners strip off emissions for reliability but this affects resale and legality. Properly rebuilt carb can last 40,000+ miles if fuel filter is changed regularly.

Estimated cost: $400-850

Typical onset: 70,000-110,000 mi

Symptoms: Howling or grinding noise from rear that changes with speed, Gear oil leak at wheel hub leaving stains on rim, Clicking during turns (outer bearing failure), Play in rear wheel when jacked up

Fix: The 7.5-inch rear axle (most common in V6 cars) has C-clip axles requiring differential cover removal to service. Bearing and seal replacement on one side takes 2-3 hours. If both sides are worn, do them together. Ignoring a leaking seal contaminates brake shoes and can lead to complete bearing disintegration and axle shaft damage.

Estimated cost: $350-650

Typical onset: 60,000-100,000 mi

Symptoms: Whining noise during steering, especially when cold, Power steering fluid puddles under front of car, Stiff steering at low speeds, Fluid level dropping every few weeks

Fix: Saginaw power steering pumps leak from shaft seal and reservoir O-rings. Pump replacement or rebuild takes 2-3 hours. Steering gearbox leaks from input shaft seal or sector shaft—requires gearbox R&R and rebuild (5-7 hours). Flushing old fluid and replacing hoses can extend life. ATF Type A was factory fill but modern Dexron works fine.

Estimated cost: $300-900