Failure mode - Ram 6.4L HEMI Gasoline (Ram HD 2019+)

Lifter / cam wear (HEMI tick source #2)

Reliability tier: aggregated - verify before ordering, see /disclosure/

Symptoms

constant valvetrain tick that does not warm-and-quiet
misfire / dead cylinder on one bank
metallic debris in the oil on neglected cases

Compare with the other causes of the same sign on this engine: ticking, knocking, rattle or whine (3 causes) · misfire, rough idle, hesitation or surging (3 causes) · metal in the fuel filter or oil

Root cause

Lifter-roller and cam-lobe wear appears across the HEMI family. The HD 6.4 is MDS-equipped (deactivating lifters on cylinders 1/4/6/7 - owner-confirmed, contrary to the older no-MDS assumption), so both standard and deactivating lifters are live service surfaces; oil neglect and high mileage drive the wear. No authoritative statistics in the open record.

Diagnosis

confirm constant (valvetrain) vs warm-and-quiet (exhaust) tick first - the cheap confusion is expensive
oil-pressure check and filter cutting before teardown
on a confirmed lifter: inspect the matching cam lobe - a flaked lobe means cam replacement; identify standard vs deactivating lifters per cylinder position before ordering

Fixes

replace lifter(s) / cam as inspection dictates; flush and correct the oil service interval afterwards ()

valvetrain - more than one option: 6.4L HEMI Valve Lifter (OEM, all-years listing), 6.4L HEMI Hydraulic Roller Lifter, deactivating (MDS, OEM), 6.4L HEMI Hydraulic Roller Lifter, standard yoke (OEM), 6.4L HEMI Push Rod (OEM), 6.4L HEMI Rocker Arm (OEM, per position), 6.4L HEMI Valve Cover Gasket (OEM)

Prevalence

common

Parts for this repair run about $25-$350: see them next to the other repairs on this engine in repair costs.