1990 DODGE RAM W350

Typical onset: 100,000-150,000 mi

Symptoms: Slipping between gears, especially 2nd-3rd shift, Delayed engagement when shifting into drive or reverse, Transmission overheating, burnt fluid smell, Complete loss of forward gears

Fix: The A727 3-speed and A518 overdrive transmissions behind both engines are undersized for towing and heavy use. Rebuild requires removal, complete teardown, clutch packs, bands, and often torque converter replacement. Expect 12-16 labor hours for R&R and rebuild.

Estimated cost: $2,200-3,800

Typical onset: 120,000-180,000 mi

Symptoms: Heavy knocking from lower engine, especially on cold start, Metallic rattling that worsens under load, Sudden loss of oil pressure, Metal shavings in oil during changes

Fix: The 360 V8 develops rod bearing and main bearing wear, often from neglected oil changes or running heavy loads. Full teardown required: crankshaft inspection/machining, new bearings, piston rings, and timing set. Short block replacement is common when crank is scored. 18-24 labor hours for in-frame rebuild or 24-30 for full removal.

Estimated cost: $3,500-6,500

Typical onset: 80,000-150,000 mi

Symptoms: Hard starting, especially when engine is warm, Loss of power under load, surging at highway speeds, Engine stalling after idling for extended periods, Air in fuel system, requires bleeding

Fix: The mechanical lift pump on the Cummins fails or develops internal leaks, sucking air. Fuel filters clog from rust in old steel tanks and lines. Replace lift pump, both fuel filters, and inspect/clean tank and sending unit. Add 3-5 hours if tank drop is needed. Basic pump/filter job is 2-3 hours.

Estimated cost: $400-1,200

Typical onset: 70,000-120,000 mi

Symptoms: Clunking from front end during turns or acceleration, Vibration at highway speeds that worsens with 4WD engaged, Grinding when engaging 4WD, hubs won't lock, Grease leaking from front axle shafts

Fix: Dana 60 front axle U-joints wear out, especially the inner joints on axle shafts. Manual locking hubs corrode and fail to engage. U-joint replacement requires axle shaft removal, pressing old joints, installing new ones. 4-6 hours for both sides plus hubs if needed.

Estimated cost: $600-1,100

Symptoms: Transmission fluid puddles under front of truck, Low fluid level, transmission slipping after short drives, Fluid spraying onto exhaust, causing smoke, Corrosion visible on steel cooler lines at radiator

Fix: Steel transmission cooler lines rust through where they mount to the radiator or along the frame rail.Lines are often replaced with pre-bent aftermarket or custom-fabricated rubber hose sections. If radiator-integrated cooler is leaking, full radiator replacement may be needed. 2-4 hours depending on rust and access.

Estimated cost: $300-800

Typical onset: 150,000-200,000 mi

Symptoms: White smoke from exhaust, especially after sitting overnight, Coolant loss with no visible external leaks, Overheating under load or towing, Milky oil on dipstick or oil cap

Fix: Both the 360 V8 and early 12-valve Cummins can blow head gaskets, though Cummins is less common. V8 requires both heads pulled, surfaces machined, new gaskets, and valve job recommended. Cummins needs head removed, resurfaced, and injectors tested. 12-16 hours for V8, 10-14 for Cummins.

Estimated cost: $2,000-3,500