1997 TOYOTA T100

Typical onset: 150,000-250,000 mi

Symptoms: Sudden catastrophic knock from bottom end—sounds like a sledgehammer in the oil pan, Metal shavings in oil, loss of oil pressure, Rod bearing wear causes connecting rod to break through block, Often happens without warning if oil changes were neglected

Fix: Complete lower end rebuild or short block replacement. We're talking 18-24 hours labor: remove engine, disassemble, inspect crank journals, replace pistons/rings/bearings, resurface or replace crankshaft. Many shops opt for a reman short block to save time. If the rod punched the block, you're buying a whole engine.

Estimated cost: $3,500-6,500

Typical onset: 80,000-150,000 mi

Symptoms: Transmission fluid puddle under front of truck near radiator, Pink or red fluid dripping—trans fluid mixing with coolant if internal cooler fails, Transmission slipping or delayed engagement after cooler failure contaminates fluid, Milky transmission fluid (coolant intrusion) or rusty coolant (trans fluid intrusion)

Fix: External cooler lines are steel and rust through where they mount to frame or radiator—2 hours to replace lines and flush system. If the internal radiator cooler fails (crack in the tank), you're replacing the radiator AND flushing the transmission; budget 4-5 hours because contaminated fluid destroys the transmission if not caught early.

Estimated cost: $400-1,200

Symptoms: Visible surface rust progressing to holes in frame rails behind cab, Rear crossmember where leaf springs mount shows heavy scaling and perforation, Rear bumper mounts pulling away from frame, Frame 'bowing' under load if crossmember integrity is compromised

Fix: This is regional—salt-belt trucks are often beyond economical repair by 20 years old. Minor surface rust can be wire-brushed, treated, and coated (4-6 hours DIY). Structural rust requires frame section replacement or welding in new steel, which is 12-20 hours of skilled labor and often not worth it on a truck this old. Inspect thoroughly before purchase.

Estimated cost: $800-4,000

Typical onset: 120,000-180,000 mi

Symptoms: External coolant seepage from head/block mating surface—usually rear bank, White smoke from exhaust on cold start (coolant burning), Overheating or coolant loss with no visible external leak, Milky oil (severe case—coolant in crankcase)

Fix: Both heads off, deck surface inspection, new gaskets, new head bolts, timing belt replacement while you're in there. 12-16 hours labor. The 3.4L is known for this between 120k-180k, especially if it's been overheated. Always replace timing belt and water pump simultaneously—you're 90% there already.

Estimated cost: $1,800-2,800

Typical onset: 100,000-160,000 mi

Symptoms: Steering wander—truck doesn't track straight, requires constant correction, Clunk or knock felt through steering wheel over bumps, Excessive play at center—can move wheel 2-3 inches before tires respond, Uneven tire wear on front end

Fix: Relay rod (center link) and idler arm bushings wear out. There was actually a NHTSA recall for relay rod failures. Inspect the entire steering linkage—pitman arm, tie rod ends, idler arm. Typical job is relay rod and idler arm replacement: 2-3 hours plus alignment. These parts are cheap but labor adds up if you're doing the whole front end.

Estimated cost: $400-800

Typical onset: 150,000+ mi

Symptoms: Hesitation or stumble under acceleration, especially uphill or under load, Hard starting after sitting—takes extended cranking, Loss of power at highway speeds, Check engine light with lean codes (P0171/P0174) if filter is severely restricted

Fix: The inline filter under the frame is easy (30 minutes), but if the in-tank sock filter is clogged, you're dropping the fuel tank to access the pump assembly—4-5 hours labor. Often combined with fuel pump replacement since you're already there. If the truck has original pump at 150k+, do both.

Estimated cost: $400-900

Typical onset: 80,000-140,000 mi

Symptoms: Clunk or thud when shifting from Park to Drive or Reverse, Vibration at idle that changes when shifting into gear, Visible cracks or separation in rubber mount under transmission tailshaft

Fix: Rubber transmission mount deteriorates and tears. Lift transmission slightly with a jack, unbolt old mount, install new one. 1-1.5 hours labor. Often done alongside rear engine mount if that's also worn. Simple job but annoying vibration if ignored.

Estimated cost: $150-300