The 1974 Gremlin is a simple, basic subcompact built on AMC's proven inline-six architecture, but suffers from typical 1970s quality control issues, marginal cooling systems, and transmission mounts that self-destruct. The straight-sixes are generally reliable if oil changes were done; the 304 V8 is overstressed in this light chassis and prone to overheating.
Transmission Mount Failure
Common · medium severityTypical onset: 50,000-90,000 mi
Symptoms: Clunking or banging when shifting into gear or accelerating, Excessive driveline vibration at idle in gear, Transmission shifter feels loose or moves excessively
Fix: Replace rubber transmission mount and inspect crossmember for cracks. The single-piece rubber mount deteriorates rapidly from heat and oil exposure. 1.5-2 hours labor including jacking and supporting the transmission safely.
Estimated cost: $150-300
Automatic Transmission (Torque-Command 904/998) Overheating and Failure
Common · high severityTypical onset: 80,000-120,000 mi
Symptoms: Slipping on 2-3 upshift or when hot, Delayed engagement from Park or Reverse, Burnt transmission fluid smell, dark or black fluid, No overdrive or stuck in second gear
Fix: These Chrysler-sourced automatics cook themselves without an auxiliary cooler, especially behind the 304 V8. Rebuild requires clutch pack replacement, band adjustment, valve body work, and new bushings. Plan 12-16 hours for removal, rebuild, and reinstall. Add auxiliary cooler during reinstall to prevent repeat failure.
Estimated cost: $1,800-2,800
Engine Overheating and Cooling System Inadequacy
Common · high severitySymptoms: Temperature gauge climbs into red zone in traffic or on hills, Steam or coolant smell from engine bay, Warped cylinder head or blown head gasket after overheating episode, V8 models particularly affected in warm climates
Fix: Factory radiator is undersized for the 304 V8 and marginal even for the sixes in hot weather. Requires radiator upgrade to 3-row or aluminum unit, new water pump, thermostat, hoses, and complete flush. If head gasket blown, add 8-12 hours for head removal, resurfacing, and reinstall. Preventive upgrade is 4-5 hours.
Estimated cost: $600-1,200 preventive, $1,500-2,500 with head gasket
Piston Ring Wear and Oil Consumption (232/258 I6)
Occasional · medium severityTypical onset: 120,000-180,000 mi
Symptoms: Blue smoke on startup or acceleration, Oil consumption 1 quart per 500-1,000 miles, Loss of compression and power on hills, Fouled spark plugs
Fix: AMC sixes use soft piston rings that wear into the bores unevenly. Ring replacement requires full disassembly, honing or boring, new rings, rod bearings, and gaskets. 20-24 hours labor. Often more cost-effective to swap in a low-mileage junkyard engine (8-10 hours) than rebuild unless you're doing it yourself.
Estimated cost: $2,200-3,500 ring job, $1,200-1,800 engine swap
Crankshaft Main Bearing Failure (304 V8)
Occasional · high severityTypical onset: 90,000-140,000 mi
Symptoms: Deep knocking from bottom of engine, worse under load, Low oil pressure at idle when hot, Metal shavings in oil or on magnetic drain plug, Sudden catastrophic failure with connecting rod through block
Fix: The 304 V8 in the Gremlin runs hot and starves the rear main bearing of oil, especially if oil changes were neglected. Requires crankshaft removal, grinding, new bearings, possibly line-boring the block. 24-30 hours labor for in-chassis rebuild. Most shops recommend short-block replacement or used engine instead.
Estimated cost: $3,500-5,500 rebuild, $1,800-2,800 used engine swap
Fuel System Vapor Lock and Carb Issues
Common · low severitySymptoms: Stalling in hot weather after short stops, Hard starting when engine is hot, Rough idle and hesitation off idle, Fuel smell in engine bay
Fix: Carter or Motorcraft carburetors mounted too close to exhaust manifold cause fuel to boil in the bowl. Requires heat shield installation, fuel line rerouting with rubber hose sections, and carburetor rebuild kit. Add electric fuel pump if mechanical pump is weak. 3-4 hours labor.
Estimated cost: $350-600
Rear Axle Seal Leaks and Bearing Noise
Occasional · low severityTypical onset: 70,000-120,000 mi
Symptoms: Gear oil puddle under rear axle, Howling or whining from rear differential, worse on deceleration, Axle seal leaking onto brake shoes causing reduced braking
Fix: AMC 20 rear axle uses shaft-mounted bearings that wear and allow seals to leak. Requires axle shaft removal, new bearings, seals, and brake inspection. 3-4 hours per side if bearings are included. Differential fluid change and gasket replacement add another hour.
Estimated cost: $400-700 both sides
Buy a straight-six model with a manual transmission if you want simple, fixable transportation; avoid the 304 V8 automatic unless you're prepared for cooling and transmission headaches.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.