1984 BUICK LESABRE

Typical onset: 80,000-140,000 mi

Symptoms: slipping between gears especially 2nd-3rd, delayed engagement when shifting to drive, whining or grinding noises, transmission overheating with burnt ATF smell, complete loss of forward gears

Fix: Full rebuild typically required once slipping starts - 12-16 hours labor. TH200-4R overdrive units are particularly weak in the direct clutch and 3-4 clutch packs. Cooler line failures often hasten death by introducing debris. Band adjustments rarely save a slipping transmission at this point.

Estimated cost: $1,800-3,200

Typical onset: 60,000-100,000 mi

Symptoms: persistent hard starting when warm, white smoke from exhaust, coolant mysteriously disappearing, catastrophic loss of power, sudden knocking followed by seizure

Fix: The Oldsmobile-based 350 diesel has catastrophic head bolt and block cracking issues - most need complete replacement or extensive rebuild by 100k. Head bolt thread pulling from the block is common. Figure 20-28 hours for long block swap or full rebuild with proper block work.

Estimated cost: $3,500-6,500

Typical onset: 120,000-180,000 mi

Symptoms: deep knocking on startup that may quiet down, low oil pressure at idle especially when hot, metallic rattling under acceleration, oil pan full of bronze/copper material, sudden catastrophic knock and seizure

Fix: Rod and main bearings wear prematurely if oil changes were neglected. Once knocking starts, full teardown needed - 18-24 hours for bottom-end rebuild with new bearings, possibly crank turning. Some mechanics opt for reman long blocks given labor costs.

Estimated cost: $2,200-4,000

Symptoms: ATF puddles under front of vehicle, transmission running hot, low fluid warnings, corroded or split steel lines at radiator connection, transmission slipping after fluid loss

Fix: Steel cooler lines rust through where they connect to radiator, especially in salt states. Replacement involves 2-3 hours to fabricate or install pre-bent lines, refill and check for leaks. Catch it early before transmission damage occurs from low fluid.

Estimated cost: $250-450

Symptoms: rough idle and stalling, black smoke under acceleration, flooding and hard cold starts, extremely poor fuel economy (under 12 mpg), hesitation off the line

Fix: Rochester carburetors (E4ME/E4MC) have multiple failure points - worn throttle shafts, deteriorated accelerator pump, stuck choke. Rebuilds run 3-5 hours but many shops now recommend replacement with reman units given ethanol damage to internal components.

Estimated cost: $400-800

Typical onset: 100,000+ mi

Symptoms: oil drips from bellhousing area, oil spots centered under transmission, gradual oil consumption, oil coating on flywheel/flexplate visible through inspection cover

Fix: Two-piece rear main seals eventually weep. Requires transmission removal - 8-12 hours labor depending on engine. Often done opportunistically during transmission rebuild. Not urgent unless losing significant oil.

Estimated cost: $600-1,200

Symptoms: intermittent gauge cluster failures, power accessories working randomly, dome lights staying on, power windows slow or stuck, random stalling that self-corrects

Fix: Early electronic modules and corroded ground points cause electrical chaos. Diagnosis takes 1-3 hours chasing grounds and testing modules. Ground point cleaning at engine block and body often resolves multiple issues. BCM replacement if failed.

Estimated cost: $150-600