1970 AMC GREMLIN

Typical onset: 50,000-80,000 mi

Symptoms: Clunking under acceleration or deceleration, Excessive shifter vibration, Transmission appears to hang lower than normal, Harsh engagement into gear

Fix: The rubber deteriorates badly on original mounts, especially on automatic-equipped cars. Replacement requires lifting the transmission slightly with a jack—typically 1.5-2 hours labor for both front and rear mounts. Aftermarket mounts are readily available.

Estimated cost: $250-450

Typical onset: varies—age and climate driven

Symptoms: Red ATF puddles under front of vehicle, Low transmission fluid warnings or slippage, Visible rust perforation on steel cooler lines, Transmission overheating on highway runs

Fix: Original steel lines rust through, especially where they pass near the frame or exhaust. If cooler lines fail and fluid is lost, automatic transmissions cook internally within minutes. Line replacement is 2-3 hours; if transmission is damaged from running dry, add 12-16 hours for rebuild. Always inspect these lines during any underbody work.

Estimated cost: $300-600 for lines only; $1,800-3,200 if transmission rebuild required

Typical onset: 60,000-100,000 mi

Symptoms: Oil spots on driveway centered under engine, Oil accumulation on bellhousing and starter, Visible seepage at oil pan rail, Low oil level between changes

Fix: Both the 232 and 258 I6 engines develop rope-style rear main seal leaks and cork oil pan gasket failures. Rear main requires transmission removal—8-10 hours labor. Oil pan is easier at 3-4 hours but requires careful alignment to avoid creating new leaks. These often occur together on higher-mileage examples.

Estimated cost: $600-900 for oil pan; $1,200-1,800 for rear main seal

Typical onset: 120,000-160,000 mi

Symptoms: Blue smoke on startup or acceleration, Excessive oil consumption—quart every 500-800 miles, Loss of power on hills, Heavy blowby visible at oil filler cap

Fix: AMC inline-sixes are long-lived but eventually suffer ring wear, especially if oil changes were neglected. Requires full engine teardown—12-16 hours for piston ring replacement, honing, and reassembly. At this mileage, plan for valve work and bearings too. Many opt for short block replacement instead at 18-22 hours.

Estimated cost: $2,200-3,500 for rings and related work; $3,500-5,500 for short block swap

Symptoms: Hard starting when hot, Flooding after sitting—gas smell in engine bay, Rough idle with black smoke, Stalling at stop signs

Fix: Carter or Holley single-barrel carbs gum up quickly with modern ethanol fuel, especially on infrequently driven examples. Float needles stick, causing flooding. Carb rebuild kits are cheap but labor runs 3-5 hours for proper cleaning, adjustment, and float setting. Replace fuel filter and check fuel pump diaphragm simultaneously.

Estimated cost: $400-700

Symptoms: Visible holes in driver/passenger floor, Soft spots when pushing on floor with foot, Surface rust bubbling through from underneath, Front subframe showing perforation near control arm mounts

Fix: Gremlins are notorious for floor and torque box rot, particularly in salt states. Front subframe rust can compromise suspension mounting points—structural and dangerous. Floor pan replacement requires 20-30 hours of welding and fabrication. Subframe work may require frame-off or extensive jig work. Inspect thoroughly before purchase.

Estimated cost: $2,500-6,000 depending on extent