1977 PONTIAC GRAND PRIX

Typical onset: 80,000-140,000 mi

Symptoms: Burnt transmission fluid smell, Slipping or delayed engagement when hot, Fluid leaking at radiator or steel cooler lines, Pink milkshake in radiator if internal cooler fails

Fix: Replace external cooler lines (rust-through common), add or replace auxiliary cooler, flush system. If radiator's internal cooler has failed and mixed ATF with coolant, budget full transmission rebuild plus radiator replacement. Cooler line job: 1.5-2 hrs. Full trans rebuild with radiator: 10-14 hrs.

Estimated cost: $300-600 for lines and aux cooler; $2,200-3,800 for rebuild scenario

Typical onset: 70,000-120,000 mi

Symptoms: Oil puddle under bellhousing area after sitting overnight, Oil film on back of engine block, Cluttered oil buildup on crossmember and transmission case, Burning oil smell from exhaust heat

Fix: Rear main seal requires transmission removal (rope seal on older 350/400/455 blocks, neoprene two-piece on 301/305). Oil pan gasket often weeps due to cork degradation and over-torqued bolts warping the rail. Rear main: 6-8 hrs. Oil pan: 2-3 hrs if crossmember doesn't fight you.

Estimated cost: $650-1,200 rear main; $280-500 oil pan

Typical onset: 60,000-100,000 mi

Symptoms: Coolant seeping from front or rear valley of intake, Rough cold idle that smooths out when warm, Coolant smell in oil or milky dipstick (severe cases), External coolant leak at intake-to-head junction

Fix: The composite and early rubber intake gaskets deteriorate; end seals fail first. Must remove intake, clean surfaces meticulously, use modern Felpro or equivalent gaskets with proper RTV application at block ends. Also inspect valley pan if equipped. 4-6 hrs on a 301/350; add an hour for 403 with tight AC compressor bracket.

Estimated cost: $550-950

Symptoms: Raw fuel smell in garage after sitting, Hard starting when hot, fires right up cold, Black smoke at idle or fuel dripping from airhorn, Severely degraded fuel economy (single digits)

Fix: Rochester Quadrajet carbs are robust but rubber-tipped needle valves harden or the float pivots wear, causing flooding. Ethanol accelerates this. Full rebuild kit with brass float if needed, or replacement with remanufactured unit. DIY rebuild: 3-4 hrs for someone experienced. Shop rebuild or replace: 2.5-3.5 hrs plus core.

Estimated cost: $350-700

Symptoms: Surface rust progressing to scaling on frame rails, Severe pitting or flaking near rear trailing arm mounts, Visible thinning at body mount points or rear kickup, Cracking or separation near spring hangers

Fix: B-body frames are stout but not galvanized. Road salt kills them. Minor surface rust is manageable with wire wheel and POR-15. Structural rust at spring mounts or crossmember areas requires welding in patch panels or sections—specialized job. Inspection is critical before purchase; repairs range from 8 hrs (minor welding) to full frame-off if terminal.

Estimated cost: $800-2,000 for sectional repair; $6,000+ if frame-off resto needed

Typical onset: 80,000-150,000 mi

Symptoms: Clunk when shifting from Park to Drive or Reverse, Vibration at idle in gear, smooths in Park/Neutral, Visible sag or torn rubber in crossmember mount

Fix: The rubber transmission mount deteriorates and the tailshaft sags, causing driveline angle issues and clunking. Replacement is straightforward: support trans with jack, unbolt crossmember, swap mount. 0.8-1.2 hrs.

Estimated cost: $120-220

Typical onset: 90,000-130,000 mi

Symptoms: Excessive play at center (more than 2 inches at wheel rim), Wandering on highway, constant correction needed, Clunking over bumps from pitman arm or center link, Visible looseness at pitman-to-sector shaft or idler arm

Fix: Saginaw manual or power steering boxes can be adjusted (sector shaft), but worn internals mean rebuild or replacement. Pitman and idler arms wear; inspect entire linkage. Box adjust: 0.5 hr. Replace box: 2-3 hrs. Full frontend refresh (arms, idler, center link): 3-5 hrs.

Estimated cost: $180-350 for adjustment/arms; $600-1,100 for box replacement and alignment