2024 Ram 3500 — Serpentine Belt Routing & Length

Quick answer

• Belt length: VIN- and engine-specific. Typical ranges:
  • 6.4L HEMI V8 (single alternator): 6‑rib, roughly 100–110 inches
  • 6.7L Cummins I‑6 (single alternator): 8‑rib, roughly 100–110 inches
  • Dual‑alternator or snow‑plow/ambulance packages use different lengths — verify by VIN
• Rib count: 6‑rib (6.4L HEMI), 8‑rib (6.7L Cummins)
• OEM belt part number (PN): Varies by engine, build date, A/C, and alternator option. Confirm with a Mopar dealer or by VIN in the Mopar parts catalog.
• Aftermarket cross‑refs (examples; confirm by VIN):
  • 6.4L HEMI: Gates K06xxxx, Dayco 506xxxx, Continental Elite 406xxxx
  • 6.7L Cummins: Gates K08xxxx, Dayco 508xxxx, Continental Elite 408xxxx
• Automatic tensioner PN: Engine‑specific; confirm by VIN. (HEMI vs. Cummins tensioners are not interchangeable.)
• Idler pulley PN: Engine‑specific; confirm by VIN. (Some builds use more than one idler.)

Note: 2024 Ram 3500s were built with two very different engines and optional dual‑alternator packages. Never order by guesswork—use the VIN to confirm exact part numbers and belt length.

Belt routing

Because we can’t display a diagram here, use this text path and photograph your existing routing before removal.

Starting at the crankshaft pulley (harmonic balancer), route the belt:

1. Crank pulley →
2. A/C compressor →
3. Idler pulley →
4. Alternator →
5. Power steering pump →
6. Water pump →
7. Automatic tensioner → back to the crank pulley

• The back (smooth) side of the belt rides on smooth pulleys like most idlers and the water‑pump pulley; the ribbed side rides on grooved pulleys (crank, alternator, A/C, power steering).
• Cummins and HEMI brackets differ, but the general order above applies. If your truck has a dual‑alternator setup, an additional alternator and idler will be included in the loop; follow the under‑hood decal and photograph the belt before removal.

How to replace the serpentine belt

Tools: serpentine belt tool or 3/8‑inch (sometimes 1/2‑inch) breaker bar for the tensioner, basic hand tools, flashlight.

1. Document the routing. Take clear photos of the existing belt from multiple angles.
2. Locate the automatic tensioner. Insert the serpentine tool or breaker bar into the tensioner square drive or onto the hex boss.
3. Relieve tension. Rotate the tensioner slowly in the direction that loosens the belt, then slip the belt off one accessible pulley (usually an idler or the alternator).
4. Remove the old belt completely. Compare length and rib count to the replacement.
5. Pre‑route the new belt. Snake it around all lower pulleys first (crank, A/C, power steering), then around the water pump and idler(s), leaving the easiest upper pulley (often the alternator) for last.
6. Load the tensioner and install. Rotate the tensioner again and slip the belt over the final pulley. Ensure the ribs are fully seated in every groove.
7. Double‑check alignment. Mis‑seated ribs will shred a new belt quickly.
8. Start the engine and watch the belt track for 30–60 seconds. Listen for chirps and verify the tensioner arm isn’t bouncing excessively.

Torque notes: If you remove any idler or the tensioner, torque fasteners to spec (varies by engine/bracket). If specs aren’t available, use factory service information for your VIN.

Replacement interval

• Normal service: Inspect every oil change; replace around 90,000–120,000 miles or 6–8 years, whichever comes first.
• Severe service (towing/hauling, high heat, dust, plow duty, or frequent idling): Inspect closely at every service and expect shorter intervals (60,000–90,000 miles). Consider replacing the belt, tensioner, and idlers as a set to restore proper tension and tracking.

Signs of a failing belt or tensioner

• Belt cracks, glazing, missing ribs, frayed edges, or chunking
• Chirp/squeal on cold start or when loads change (A/C on, steering to lock)
• Slapping or fluttering belt, excessive black rubber dust near pulleys
• Power steering feels heavy at idle, battery light or dimming lights, A/C performance drops at idle
• Tensioner arm oscillates or sits near its stop, rough or noisy idler bearings, wobbling pulleys

If any of the above are found, inspect the entire front‑end accessory drive: belt, tensioner, idlers, alternator and A/C pulleys, and the water‑pump and power‑steering pulleys for wobble or misalignment. On Cummins engines, also check for bracket wear and any added‑equipment pulleys if equipped with dual alternators.

Engine‑option variation (read before ordering)

• 6.4L HEMI V8: Typically uses a 6‑rib belt. Length depends on A/C presence (most 3500s have A/C) and bracket revisions.
• 6.7L Cummins I‑6: Typically uses an 8‑rib belt. Available with single or dual alternators; dual‑alt setups and certain upfitter packages use different belts, idlers, and tensioners.
• Build date changes: Mid‑year component revisions can change part numbers. Always confirm by VIN in the Mopar catalog or a trusted aftermarket catalog (Gates, Dayco, Continental).

Tip: When replacing a worn belt, strongly consider a new automatic tensioner and idler(s). A weak tensioner will quickly glaze or shred a new belt, especially on heavy‑duty trucks that tow or idle extensively.

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