2015 DODGE RAM 3500

Typical onset: 80,000-150,000 mi

Symptoms: Harsh or delayed shifts, especially 2-3 and 5-6 upshifts, Slipping under load or when towing, Limp mode with transmission codes P0871, P0868, or P0731, Burnt transmission fluid smell or dark/metallic fluid

Fix: Full rebuild with upgraded clutch packs, valve body updates, and torque converter replacement. Figure 18-24 labor hours for a quality rebuild with beefed-up internals. Tuned or deleted trucks fail sooner—stock power helps longevity but won't prevent eventual wear.

Estimated cost: $4,500-7,500

Typical onset: 60,000-100,000 mi

Symptoms: Vibration or shudder at 40-50 mph during light acceleration, Feeling like driving over rumble strips when converter tries to lock, Intermittent P0740 or P0742 codes, Shudder worsens when towing or under load

Fix: Torque converter replacement, often combined with transmission service and valve body inspection. Transmission must come out—12-16 hours labor. Fluid changes every 30k can delay this but won't prevent it on high-mileage units.

Estimated cost: $2,800-4,200

Typical onset: 70,000-120,000 mi

Symptoms: Check engine light with codes P0871, P0848, or P2767, Erratic shifting patterns or stuck in one gear, Delayed engagement into drive or reverse, Transmission running hot

Fix: Solenoid pack replacement requires pan drop and valve body removal. Many techs replace the entire valve body assembly to avoid repeat failures—8-12 hours labor. OEM Mopar parts strongly recommended over aftermarket.

Estimated cost: $1,200-2,400

Typical onset: 90,000-140,000 mi

Symptoms: ATF puddles under truck, often near radiator area, Low transmission fluid warnings or burnt smell, Cooler line corrosion or rubbing damage at frame contact points, Loss of line pressure causing shift issues

Fix: Replace cooler lines and inspect external cooler for integrity. Lines corrode where they contact the frame—aftermarket stainless or upgraded lines recommended. 3-5 hours labor depending on accessibility and whether external cooler needs replacement.

Estimated cost: $600-1,400

Typical onset: 80,000-130,000 mi

Symptoms: Diesel fuel odor in cab or under hood, Fuel weeping from filter housing or return lines, Hard starting when fuel prime is lost overnight, Visible wet spots on top of fuel filter canister

Fix: Replace fuel filter housing O-rings and gaskets, inspect all quick-connect fittings. Often combined with fuel filter service—2-3 hours labor. Not the CP4 pump itself failing here, just seals and housing components aging out.

Estimated cost: $400-750

Typical onset: 100,000+ mi

Symptoms: Clunking or banging when shifting into gear, Excessive drivetrain movement when accelerating or braking, Visible sagging or torn rubber on transmission mount, Vibration through floor at highway speeds

Fix: Replace transmission mount and inspect crossmember for cracks—common on trucks used for towing. 2-3 hours labor with transmission supported properly. Upgraded polyurethane mounts available for heavy-duty use.

Estimated cost: $350-650

Typical onset: 70,000-110,000 mi

Symptoms: Sloppy shifter feel or excessive play in gear selector, Difficulty getting into park or reverse, Shifter doesn't align with gear indicator on dash, Plastic bushing fragments found under truck

Fix: Replace shift cable and bushings at both transmission and column ends. Dorman makes a popular upgraded bushing kit—1.5-2.5 hours labor. Cheap fix that makes shifting feel new again.

Estimated cost: $250-500