1988 CHEVROLET BLAZER

Typical onset: 80,000-140,000 mi

Symptoms: Slipping between 3rd and overdrive, especially under load, Delayed engagement into drive or reverse after sitting, Burnt transmission fluid smell and dark brown/black fluid, Complete loss of forward gears, stuck in 2nd or 3rd

Fix: The 700-R4 overdrive clutches and 3-4 accumulator springs wear out. Most shops recommend full rebuild or reman unit over band-aid repairs because torque converter and pump often need work too. Expect 8-12 hours labor for R&R plus rebuild time, or 6-8 hours for reman swap.

Estimated cost: $1,800-3,200

Typical onset: any mileage—age-related

Symptoms: Intermittent stalling when fuel tank drops below half, No-start condition after sitting, especially in hot weather, Fuel gauge erratic or stuck on empty, Engine surging or hesitation at highway speeds

Fix: Steel fuel tanks rust from the inside out; pickup sock clogs, pump fails, and sender corrodes. Drop the tank (2-3 hours), replace pump assembly and sender unit. Often find rust flakes and water in the tank requiring replacement or professional cleaning.

Estimated cost: $450-900

Typical onset: 100,000-180,000 mi

Symptoms: Oil dripping from bellhousing inspection cover onto starter, Puddle forms under transmission bellhousing after parking overnight, Clutch slippage (manual) or fluid cross-contamination (auto), Oil consumption increases but no visible leaks up top

Fix: The two-piece rear main seal design on these small-blocks is notorious. Requires transmission removal—6-8 hours labor for 4WD models due to transfer case. Often find worn crankshaft surface requiring repair sleeve installation, adding 1-2 hours.

Estimated cost: $800-1,500

Typical onset: any—fuel quality dependent

Symptoms: Rough idle with intermittent stumble, Hard starting when engine is hot, Black smoke from exhaust and poor fuel economy, Check engine light with lean/rich codes

Fix: The two large injectors in the TBI unit clog from varnish buildup or stick open/closed. Professional ultrasonic cleaning works sometimes, but injector replacement is more reliable. Remove TBI unit (1 hour), clean or replace injectors, replace gaskets. Pressure regulator often needs replacement at same time.

Estimated cost: $250-550

Typical onset: 70,000-150,000 mi

Symptoms: 4WD will not engage—dash indicator blinks or stays off, Grinding noise from front differential when engaging 4WD, Front wheels do not pull in 4WD on slippery surfaces, 4WD engages but disengages randomly while driving

Fix: The thermal actuator on passenger side of front axle uses engine vacuum to lock the passenger-side axle shaft. Diaphragm fails or linkage seizes. Replace actuator (1.5-2 hours) or convert to manual cable setup for reliability. Check vacuum lines and switch at transfer case during diagnosis.

Estimated cost: $200-450

Symptoms: Visible rust perforation along rocker panels and cab corners, Body visibly sagging or gaps between bed and cab increasing, Doors difficult to close or alignment off after closing, Soft or crumbling metal around body mount bolt locations

Fix: Frame and body mounts rust severely in salt states. Inspect carefully before purchase—body mounts are replaceable (8-12 hours for all eight plus hardware), but frame rot means scrap. Cab corners and rockers require welding or bolt-on patch panels. This is a structural safety issue, not cosmetic.

Estimated cost: $1,200-4,500

Typical onset: 120,000-200,000 mi

Symptoms: Hard starting requiring extended cranking, especially cold, Loss of power and black smoke under acceleration, Fuel in crankcase oil—dipstick smells like diesel, Engine dies at idle or won't maintain idle speed

Fix: The Stanadyne DB2 mechanical injection pump wears internally, loses pressure, or the internal transfer pump fails. Replacement requires timing procedure and often new injectors due to contamination. Budget 6-8 hours labor plus pump core charge. These pumps are getting scarce and expensive.

Estimated cost: $1,800-3,000