The 1999 Durango is a body-on-frame SUV sharing DNA with Dakota pickups. Solid axles front and rear make it durable off-road, but the 46RE/45RFE transmissions and certain V8 engine internals are notorious weak points that can turn expensive fast.
46RE/45RFE Transmission Failure (Cooler Line & Internal)
Common · high severityTypical onset: 90,000-150,000 mi
Symptoms: Delayed or harsh shifts, especially 2-3 upshift, Transmission fluid in coolant or coolant in transmission (strawberry milkshake in overflow), Slipping under load or complete loss of forward gears, Whining noise from torque converter
Fix: The radiator-mounted cooler fails internally, cross-contaminating fluids and destroying clutch packs and torque converter. Requires transmission rebuild or replacement, radiator replacement, and complete flush of cooling system. Budget 12-16 hours labor for full rebuild, plus R&R time. External cooler addition is mandatory to prevent repeat failure.
Estimated cost: $2,800-4,200
5.9L Magnum Engine Bearing and Piston Failure
Occasional · high severityTypical onset: 120,000-180,000 mi
Symptoms: Heavy rod knock on cold start that may quiet when warm, Low oil pressure at idle (below 10 psi hot), Metal shavings in oil or on magnetic drain plug, Catastrophic failure with sudden loss of power and loud banging
Fix: The 5.9L suffers main and rod bearing wear, often from inadequate oiling to cylinder walls. Piston skirt wear also common. Requires complete short block replacement or full engine rebuild with machining. 20-28 hours labor for in-chassis rebuild, more for removal. Many techs recommend long-block replacement instead of rebuild due to core condition.
Estimated cost: $4,500-7,500
Front Hub Bearing Failure (Dana 44 Front Axle)
Common · medium severityTypical onset: 80,000-130,000 mi
Symptoms: Grinding or humming noise that increases with speed, Noise changes pitch in turns (louder on one side), Steering wheel vibration at highway speeds, Excessive wheel play when jacked up
Fix: Unit bearing design on 4WD models is sealed and non-serviceable. Bearing races rust and pit, especially in salt states. Each side requires hub assembly replacement, approximately 2-3 hours labor per side. Both sides often need attention within 10,000 miles of each other. Recall covered some early failures but most are wear items now.
Estimated cost: $400-650 per side
Plenum Pan Gasket Leak (3.9L and 5.2L V8)
Common · medium severityTypical onset: 70,000-120,000 mi
Symptoms: Rough idle, especially when cold, Hesitation on acceleration, Oil consumption without external leaks, Check engine light with lean codes (P0171/P0174)
Fix: Intake plenum gasket deteriorates, allowing oil vapor from crankcase to be drawn into cylinders and creating vacuum leaks. Requires upper intake removal and gasket replacement with updated Hughes Engines kit (Mopar superceded). 4-6 hours labor. While in there, replace oil pressure sending unit and inspect distributor O-ring.
Estimated cost: $600-950
Ball Joints (Both Upper and Lower)
Common · high severityTypical onset: 90,000-140,000 mi
Symptoms: Clunking over bumps from front end, Steering wander or loose feel on center, Tire wear on inside or outside edges, Visible grease boot tears or excessive play in joint
Fix: Heavy vehicle weight accelerates ball joint wear, especially uppers. These are load-bearing on this suspension geometry and failure can separate the knuckle. Both uppers and lowers should be replaced together. 5-7 hours labor for complete front end, requires alignment after. Some techs press in new joints, others use replaceable-joint control arms.
Estimated cost: $1,200-1,800
Fuel Pump and Tank Issues
Occasional · medium severityTypical onset: 100,000-160,000 mi
Symptoms: No-start or stalling when fuel level drops below 1/4 tank, Whining noise from rear when key is on, Rough running or surging under load, Check engine light with fuel trim or pressure codes
Fix: In-tank pump wears out, but tank strap corrosion and filler neck rust are equally common in rust belt. Pump replacement requires dropping 25-gallon tank, 2-3 hours labor. While tank is down, inspect and replace straps and hardware, check filler neck and vapor lines for rust-through. NHTSA recall addressed some strap failures but corrosion continues.
Estimated cost: $650-1,100
Steering Gear Box Leaks and Wear
Occasional · medium severityTypical onset: 110,000-170,000 mi
Symptoms: Power steering fluid leaking from sector shaft seal, Play at steering wheel center (more than 2 inches free play), Groaning when turning at low speeds, Wandering on highway requiring constant correction
Fix: Recirculating ball steering box develops sector shaft seal leaks and internal wear. Rebuilds rarely last, replacement with remanufactured unit is standard practice. 3-4 hours labor, requires alignment. Flush and bleed system completely, inspect pump and high-pressure hose at same time.
Estimated cost: $750-1,200
Buy only if transmission has been rebuilt with external cooler added and you can verify consistent oil changes — otherwise budget $5,000 for deferred maintenance in first year.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.