1979 CHEVROLET BLAZER

Typical onset: 80,000-140,000 mi

Symptoms: Slipping between 1st and 2nd, especially under load, Delayed engagement when shifting into drive or reverse, Burnt transmission fluid smell, dark or metallic-flecked fluid, Hard shifts or no upshift past second gear

Fix: Full rebuild required in most cases; includes new clutch packs, bands, seals, and often the torque converter. Oil cooler lines frequently corrode and contaminate fluid, accelerating wear. Budget 12-16 hours labor for a proper rebuild with valve body work.

Estimated cost: $1,800-3,200

Symptoms: Hard starting when warm, floods easily, Rough idle, black smoke from tailpipe, Hesitation or bog on acceleration from a stop, Gas smell in cab, fuel dripping from carb base

Fix: The Quadrajet's float needles, accelerator pump diaphragms, and power-piston seals fail from ethanol fuel. A quality rebuild kit and 3-4 hours labor resolves it if the carb body isn't warped. Some techs swap to an Edelbrock 1406 to avoid repeat issues (add $400 for new carb).

Estimated cost: $350-650

Symptoms: Visible rust-through on frame rails behind cab or near rear spring hangers, Body sags or leans to one side, doors won't close square, Cracked or completely rotted rubber body mounts, Steering wander due to frame flex

Fix: Rust-belt trucks often need frame section replacement or welded reinforcement plates; body mounts ($15 each) are a 4-hour job if hardware isn't seized. Severe cases require frame-off work, which is 20+ hours. Surface rust is manageable; structural perforation is a write-off unless you're committed to welding.

Estimated cost: $600-1,200 (mounts only); $3,000+ (frame repair)

Typical onset: 60,000-100,000 mi

Symptoms: Coolant loss with no visible external leaks, White smoke from exhaust on cold start, Rough idle, misfires, or oil contamination in coolant, Coolant smell from exhaust or inside cab vents

Fix: The composite intake gaskets fail and allow coolant into the valley or cylinders. Replacement requires manifold removal, new gaskets, and often new valley pan. 5-7 hours labor; use Fel-Pro or OEM-quality gaskets, not cheap paper sets. On 454s, add time for exhaust manifold removal.

Estimated cost: $650-1,100

Typical onset: 70,000-130,000 mi

Symptoms: Oil puddle directly under the bellhousing area, Oil coating the starter and lower bellhousing, Clutch slippage if manual (oil contamination), though most are automatics

Fix: Two-piece rope seal design leaks as it hardens with age. Requires transmission removal; 6-8 hours labor. Most techs now install a one-piece neoprene retrofit seal for longevity. Check for crankshaft wear in the seal contact area—if grooved, you'll need a repair sleeve ($40) or machine work.

Estimated cost: $700-1,300

Symptoms: Fuel gauge reads empty regardless of actual fuel level, Gauge bounces erratically or pegs at full, Intermittent gauge operation over bumps

Fix: The float arm corrodes or the rheostat wears out inside the tank. Requires tank drop (2-3 hours), sending unit replacement, and sometimes new fuel pickup sock. Good time to replace old rubber filler hose and steel fuel lines if crusty. Aftermarket units are hit-or-miss; OEM-spec replacements are worth the $30 upcharge.

Estimated cost: $350-600

Typical onset: 90,000+ mi

Symptoms: 2-3 inches of dead play at the wheel before tires respond, Constant steering corrections on highway, Clunking from steering box when turning lock-to-lock, Leaking power steering fluid from box seals

Fix: Saginaw 605 series gearbox wears internally; sector shaft and worm gear develop slop. Rebuild kits exist but most shops recommend a reman unit (4-5 hours labor). Also inspect pitman and idler arms—these wear simultaneously and make diagnosis tricky. Alignment after replacement is mandatory.

Estimated cost: $550-950