The 1998 Ram 1500 is a workhorse truck with bulletproof drivetrains when maintained, but the 46RE/47RE transmissions are the Achilles heel, and the 5.9L Magnum has well-documented intake manifold plenum gasket failures that cause lean codes and rough idle.
46RE/47RE Transmission Failure
Common · high severityTypical onset: 100,000-150,000 mi
Symptoms: Delayed or harsh 2-3 shift, Loss of overdrive or limp mode, Transmission slipping under load, Burnt fluid smell and dark red/brown fluid
Fix: These overdrive automatics eat clutch packs and bands, especially if fluid service was neglected. The governor pressure solenoid and sensor also fail frequently. Rebuild requires 12-16 hours including R&R. Many shops won't touch a rebuild under $2K anymore; expect closer to $2500-3000 for a quality job with updated parts. The transmission oil cooler line fittings at the radiator also corrode and leak, contaminating fluid—always inspect during service.
Estimated cost: $2,500-3,500
Intake Manifold Plenum Gasket Failure (5.9L)
Common · medium severityTypical onset: 80,000-120,000 mi
Symptoms: Rough idle and hesitation on acceleration, P0171/P0174 lean codes, Whistle or hissing from intake area, Poor fuel economy
Fix: The composite gasket under the plenum pan deteriorates and allows vacuum leaks. This is a known Magnum V8 defect. Repair involves removing the upper intake plenum, replacing gasket with updated Mopar part or Felpro upgrade kit—4 to 5 hours labor. While you're in there, replace the PCV valve and inspect throttle body gasket. DIY-friendly if you have the tools.
Estimated cost: $400-700
Dashboard Cracking
Common · low severitySymptoms: Cracks forming along top of dash near windshield, Warping and separation of dash cover, Cosmetic degradation from UV exposure
Fix: The '94-'01 Ram dash is infamous for cracking in sun exposure—it's almost universal in southern climates. Not a mechanical issue but affects resale and interior aesthetics. Replacement involves full dash removal, which is 8-10 hours labor, and used dashes crack too. Dash covers are the practical solution at $50-100. Some owners have won class-action settlements for this defect in the past.
Estimated cost: $800-1,500
Ball Joint Wear
Common · high severityTypical onset: 80,000-130,000 mi
Symptoms: Clunking over bumps from front suspension, Wandering or loose steering feel, Uneven tire wear on inside edges, Visible play when prying on suspension
Fix: These trucks chew through upper and lower ball joints, especially if used for towing or off-road. The uppers often go first. Replacing all four corners with quality parts (Moog or OE) is 4-6 hours labor. This is a safety-critical repair—worn ball joints can separate. Always do an alignment after replacement.
Estimated cost: $600-1,200
Exhaust Manifold Cracking (5.9L)
Occasional · medium severityTypical onset: 100,000+ mi
Symptoms: Ticking or tapping noise from engine bay, worse when cold, Exhaust smell in cabin, Visible soot or rust stains on manifold
Fix: The cast-iron manifolds on the 5.9L develop cracks between ports due to heat cycling, most commonly on the passenger side. Replacement with upgraded aftermarket headers or OE manifolds takes 3-4 hours per side including broken stud extraction (almost guaranteed). Budget extra for penetrating oil and stud removal time—rusted fasteners are the norm.
Estimated cost: $500-900
Fuel Pump Failure
Occasional · high severityTypical onset: 120,000-180,000 mi
Symptoms: No start or extended cranking, Stalling or hesitation at highway speeds, Whining noise from fuel tank, Loss of power under load
Fix: In-tank fuel pump assemblies fail from age and contamination. The pump, sending unit, and strainer should all be replaced as an assembly. On these trucks, you drop the tank—3 to 4 hours labor. Running the tank low frequently accelerates pump wear. Always use quality fuel and replace the fuel filter every 30K.
Estimated cost: $500-800
AC Blend Door Failure
Occasional · low severityTypical onset: 100,000+ mi
Symptoms: Heat stuck on full or no heat control, Clicking noise from behind dash, Inability to switch between hot and cold air
Fix: The plastic HVAC blend door actuator arm breaks, leaving you stuck on heat or cold. Factory fix requires full dash removal—dealership quoted 8-12 hours. Aftermarket kits allow repair through glove box access in 2-3 hours, but it's tight quarters. This is a common Chrysler defect across platforms. The actuator motor itself can also fail.
Estimated cost: $300-1,200
Buy one if the transmission has been rebuilt or well-maintained with records—the engines are near-unkillable, but budget $2-3K for a trans rebuild if it hasn't been done.
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.