1977 PONTIAC FIREBIRD TRANS AM

Typical onset: 70,000-120,000 mi or on any engine that sat long-term

Symptoms: loud ticking or clattering from valve train at idle, loss of power and rough idle, metal shavings in oil, check oil pressure—cam wear can starve lifters

Fix: Requires intake manifold removal, lifter valley teardown, cam replacement, all 16 lifters, new timing set, and often pushrods. If the cam ate itself, expect machine work on lifter bores. 12-18 hours labor for cam swap; if cylinders are scored from debris, you're into a full rebuild.

Estimated cost: $2,000-4,500

Typical onset: any—age and heat cycling are the killers

Symptoms: clunk on acceleration or deceleration, transmission sag visible under car, ATF drips or spray near crossmember, burnt ATF smell after highway runs if cooler is clogged

Fix: Transmission mount is a 1-2 hour job—cheap part, but access is tight. Oil cooler lines rust and crack where they loop over the crossmember; replacement lines are 2-3 hours because of routing and flare fittings. If the cooler itself is clogged, add another hour and $150 for a new unit.

Estimated cost: $250-800

Typical onset: 60,000+ mi

Symptoms: oil puddle centered under bellhousing, clutch slippage if manual (oil-soaked disc), oil coating on flywheel/flexplate at inspection cover

Fix: Transmission must come out—4-6 hours labor for a TH350/400 with exhaust removal. Two-piece rear main seal is rope-style on these Pontiac and Olds engines; proper installation is fiddly, and many mechanics over-torque the cap causing immediate re-leak. Parts are cheap, labor is not.

Estimated cost: $800-1,400

Symptoms: stumble off idle or bog on acceleration, black smoke and fuel smell—power valve ruptured, idle creep or high idle from worn throttle shafts, fuel leaking from accelerator pump well or float bowl gaskets

Fix: Full Quadrajet rebuild kit and careful attention to float level, power valve, and accelerator pump. Budget 3-4 hours if you're meticulous; many shops just swap for a reman or Edelbrock clone (another 2 hours for tuning). Ethanol fuel eats the original rubber parts.

Estimated cost: $350-750

Symptoms: visible rust perforation in footwells or under carpet, spongy feel when jacking at torque boxes, cracking paint or bubbling on rocker panels, water intrusion and musty smell inside

Fix: Torque boxes tie the subframe to the unibody; if they're gone, the car is unsafe and won't handle. Patch panels exist, but proper repair is 20-40 hours of cutting, welding, and finish work. Floor pans are easier—AMD makes full replacements—but still 12-16 hours per side with seam sealing.

Estimated cost: $3,000-8,000

Typical onset: 80,000+ mi

Symptoms: excessive play at the steering wheel—often 2-3 inches before wheels respond, wandering on highway, constant correction needed, clunking over bumps from inner or outer tie rod ends

Fix: Saginaw manual boxes can be adjusted (30 minutes), but if the sector shaft is worn, you need a rebuild or replacement (3-4 hours). Tie rod ends are straightforward—1.5 hours per side with alignment. Power steering boxes leak from the sector shaft seal and need a rebuild around 100k mi (6-8 hours).

Estimated cost: $400-1,200

Symptoms: fuel gauge reads empty or full regardless of actual level, fuel smell in trunk or cabin, rust perforation visible on tank straps or at filler neck, starting issues if in-tank sock filter is clogged with rust

Fix: Sending unit replacement is 2 hours—drop tank, swap unit, test gauge. If the tank is rusty inside, budget for a replacement or professional cleaning and sealing (Caswell kit, 8-10 hours DIY). Ethanol accelerates internal corrosion on original tanks. Filler neck and vent lines also rust through.

Estimated cost: $300-1,000