1973 PONTIAC GRAND AM

Typical onset: any mileage on original cooler

Symptoms: pink or milky transmission fluid, transmission slipping or delayed engagement, coolant looks oily or has transmission fluid sheen, overheating transmission

Fix: Replace external transmission cooler or repair internal radiator cooler, flush transmission completely, replace filter and fluid. If contamination caused clutch damage, full rebuild needed. 3-5 hours for cooler replacement and flush, 12-18 hours if rebuild required.

Estimated cost: $400-800 for cooler/flush, $2,200-3,500 if transmission rebuild needed

Typical onset: 80,000-150,000 mi

Symptoms: blue smoke on startup or acceleration, excessive oil consumption (1+ qt per 500 miles), low compression on multiple cylinders, blowby visible at oil filler cap

Fix: Requires engine teardown, cylinder honing or boring, new pistons and rings. Most opt for complete rebuild at this point. 20-30 hours for proper rebuild including machine work.

Estimated cost: $3,500-6,000

Typical onset: 100,000+ mi or neglected oil changes

Symptoms: deep knocking from bottom end, especially under load, metallic rattling at idle, sudden drop in oil pressure, metal shavings in oil or filter

Fix: Engine must come out for crankshaft inspection, grinding, and main bearing replacement. Often turns into full rebuild once it's apart. 25-35 hours including R&R.

Estimated cost: $4,000-7,500

Typical onset: 50,000+ mi on original mounts

Symptoms: clunk when shifting into drive or reverse, excessive driveline vibration at idle in gear, visible sagging of transmission tail, harsh engagement

Fix: Replace rubber transmission mount and crossmember bushings. Simple job but requires supporting transmission. 1.5-2.5 hours.

Estimated cost: $150-350

Typical onset: not mileage-driven, ethanol fuel damage

Symptoms: fuel smell when parked, hard starting when hot, black smoke and rough idle, fuel dripping from carburetor, crankcase diluted with raw fuel

Fix: Rebuild or replace carburetor with emphasis on float, needle valve, and seats. These Rochester units don't tolerate modern ethanol well. 3-5 hours for proper rebuild and tuning.

Estimated cost: $400-800

Typical onset: 100,000+ mi

Symptoms: rattling from front of engine on cold start, erratic timing that won't stay adjusted, check timing marks show 4-8 degrees of slop, rough idle and poor performance

Fix: Replace timing chain, gears, and often the dampener while front cover is off. 6-9 hours with proper front-end disassembly.

Estimated cost: $800-1,400