1977 AMC GREMLIN

Typical onset: 70,000-120,000 mi

Symptoms: Transmission fluid mixing with coolant (strawberry milkshake in radiator), Erratic shifting or slipping, Overheating transmission, Complete transmission failure after cooler breach

Fix: The internal transmission cooler in the radiator fails, allowing coolant and ATF to mix. This contaminates both systems and destroys the automatic transmission within days if not caught early. Requires new radiator with external cooler bypass, complete transmission flush or rebuild, and cooling system flush. 8-12 hours labor if caught early; 15-20 hours if transmission needs rebuild.

Estimated cost: $800-3,500

Typical onset: 120,000-180,000 mi

Symptoms: Deep knocking noise from bottom end, especially when cold, Low oil pressure at idle, Metal shavings in oil, Sudden catastrophic failure with rod knock

Fix: The 258 I6 is bulletproof when maintained, but extended oil change intervals or low oil levels destroy main bearings and score the crank. Requires complete engine disassembly, crankshaft grinding or replacement, new bearings, and often pistons/rings while you're in there. Most shops recommend short block replacement or full rebuild. 18-25 hours labor for proper rebuild.

Estimated cost: $2,800-5,500

Typical onset: 60,000-100,000 mi

Symptoms: Severe clunking when shifting from Park to Drive, Vibration at idle, Visible drivetrain movement when accelerating, Transmission tail housing sagging

Fix: The rubber transmission mount deteriorates from age and heat. The transmission drops, misaligns the driveshaft, and stresses the shift linkage. Straightforward replacement with crossmember removal. 1.5-2.5 hours labor.

Estimated cost: $150-350

Symptoms: Hard starting when hot, Black smoke and fuel smell, Flooding after sitting, Rough idle and hesitation, Fuel dripping from carburetor

Fix: The Carter BBD or YF carburetors dry out, float needles stick, and fuel pumps lose pressure. Old fuel gums up passages. Most need carburetor rebuild, fuel filter replacement, and often a new fuel pump. Adjustment is critical. 3-5 hours for carb rebuild and fuel system service.

Estimated cost: $400-800

Typical onset: 100,000-150,000 mi

Symptoms: Blue smoke on startup and acceleration, Excessive oil consumption (1 qt per 500-1000 miles), Loss of compression, Fouled spark plugs

Fix: Rings wear from heat cycling and old oil. Compression drops, oil burns. Requires engine removal, disassembly, cylinder honing, new pistons or rings, and often valve work while you're there. 16-22 hours labor for proper ring job with head work.

Estimated cost: $2,200-4,000

Typical onset: 80,000-140,000 mi

Symptoms: Oil dripping from bell housing area, Oil spots under rear of engine, Transmission bellhousing wet with oil

Fix: The rope-style rear main seal hardens and leaks. Requires transmission removal to access. Often done during clutch or transmission work. 4-6 hours labor if doing seal only.

Estimated cost: $350-700