1987 CHEVROLET ASTRO

Typical onset: 80,000-140,000 mi

Symptoms: Slipping between 3rd and overdrive, especially under load, No reverse or delayed engagement into reverse, Burned transmission fluid smell, dark or metallic fluid, Harsh 1-2 shift or won't shift out of first

Fix: The 700R4 in these vans dies from inadequate cooling and weak internal clutches. Rebuild requires 8-12 hours labor, must include upgraded clutch pack, better servo, and auxiliary cooler installation to prevent repeat failure. Many shops won't warranty a rebuild without adding the external cooler.

Estimated cost: $1,800-2,800

Typical onset: 70,000-120,000 mi

Symptoms: Hard starting when engine is hot, starts fine cold, Stalling at idle after warm-up, Hesitation or stumble on acceleration, Check engine light with codes 33 or 34 (MAP sensor)

Fix: The in-tank fuel pump weakens, TBI pressure regulator diaphragm leaks fuel into vacuum line, or fuel filter clogs (should be changed every 30k but rarely is). Diagnosis takes 1 hour, pump replacement is 2-3 hours dropping the tank, regulator is 1.5 hours. Always do fuel filter first—it's often the culprit and takes 0.5 hours.

Estimated cost: $350-950

Symptoms: Transmission fluid spots under vehicle near radiator, Rapid transmission fluid loss, visible dripping at cooler lines, Corroded or flaking steel lines where they connect to radiator, Pink or red coolant (catastrophic—cooler failed inside radiator)

Fix: Steel cooler lines rust through at the radiator and frame contact points, especially in salt states. Line replacement is 2-3 hours including fabrication or pre-bent replacements. If radiator internal cooler fails and mixes coolant with ATF, you need immediate transmission flush (add 3 hours) or the trans is toast within 500 miles. Replace with external cooler setup.

Estimated cost: $300-600 for lines, $2,200-3,200 if radiator contaminated trans

Typical onset: 150,000-200,000 mi

Symptoms: Loud knocking from bottom of engine, worse with RPM, Metal shavings in oil or glitter on dipstick, Sudden loss of oil pressure, Visible crank movement or wobble at harmonic balancer

Fix: The 4.3L can spin main or rod bearings if oil changes were neglected or if run low on oil. Crank journals wear undersized and require machine work or replacement. In-chassis rebuild requires 18-24 hours, or 12-15 hours for engine removal and replacement with used/reman long block. Most cost-effective fix is used engine swap if body is good.

Estimated cost: $2,500-4,500 rebuild, $1,800-2,800 used engine swap

Symptoms: No-start when engine is fully hot, starts fine after cooling 30+ minutes, Intermittent stalling in hot weather or after extended driving, Tachometer drops to zero while driving then engine dies, Crank sensor or ignition module codes

Fix: The HEI distributor ignition module sits directly on the distributor housing and cooks itself to death from engine heat, especially in summer. Module replacement takes 0.8 hours and requires distributor removal or working blind. Pickup coil in distributor also fails. Keep a spare module in the glovebox—it's a known roadside breakdown item.

Estimated cost: $180-320

Typical onset: 100,000-150,000 mi

Symptoms: Howling or whining from rear that increases with speed, Clunking when engaging/disengaging locker, Metal shavings in differential fluid, Hot differential after driving, burning smell

Fix: The corporate 10-bolt with G80 limited slip sees side bearing wear and sometimes destroys the locker mechanism if abused. Bearing replacement requires 4-6 hours with setup and preload adjustment. If locker is damaged, add 2 hours and $400 in parts, or just replace with standard carrier.

Estimated cost: $600-1,200