Both trucks Squawk over their engines. The tiebreak: the Ram's failures bill the owner, the Sierra's headline is on GM.

The loudest 2021 complaint. The 5.7 Hemi's exhaust-manifold bolts snap and the manifolds crack — owners report a tick that grows louder over time and, in the worst cases, exhaust fumes leaking into the cab, with dealers acknowledging it as a known issue. It's a leak repair that gets more involved (and more expensive) the longer it's left. On the test drive, cold-start and listen for a tick that's loudest when the engine is cold and eases as it warms — the classic manifold-leak signature — distinct from the deeper valvetrain lifter tick.

Sources: NHTSA complaint database, 2021 Ram 1500 · Independent mechanic channel transcripts (5.7 Hemi manifold/cam/lifter; eTorque MGU teardown)

On eTorque trucks, the 48-volt mild-hybrid runs off a belt-driven motor-generator unit that independent mechanics call 'notoriously known for going bad' — essentially a complex alternator-plus-motor that stop/start duty wears hard. Owners report the dealer condemning the eTorque and advising against driving. Repair costs vary widely by shop: one mechanic recounts a job another shop quoted around $5,000 (nearly totaling the truck) that an independent did for under $1,000. A separate PCM recall (23V265) covers a 5.7 eTorque fuel-mixture fault that can stall the engine. A non-eTorque Hemi or the Pentastar V6 avoids this system entirely.

Sources: NHTSA complaint database, 2021 Ram 1500 · NHTSA recall database and manufacturer communications (recall 23V265; CSN W82; camera/airbag recalls) · Independent mechanic channel transcripts (5.7 Hemi manifold/cam/lifter; eTorque MGU teardown)

The Hemi's valvetrain risk runs alongside the manifold issue: a worn hydraulic lifter and cam lobe tick and eventually misfire, sometimes with low oil pressure and, in the worst reports, catastrophic engine failure. Independent mechanics quote a cam-and-lifter repair at a minimum around $4,500, with engine replacement often recommended once metal shows in the oil. The recent file also carries oil-pan corrosion and stall-with-no-warning reports. Cold-start and listen for a deep valvetrain tick separate from the manifold leak.

Sources: NHTSA complaint database, 2021 Ram 1500 · Independent mechanic channel transcripts (5.7 Hemi manifold/cam/lifter; eTorque MGU teardown)

The defining 2021 issue if the truck has the 6.2L — and the Sierra Denali, which skews to that engine, is disproportionately affected. GM recalled about 597,571 vehicles (2021–2024 Sierra, Silverado, Tahoe, Yukon, Escalade) for connecting-rod and crankshaft defects that put debris in the oil and can cause sudden engine failure — 'no warning, just died' — with NHTSA expanding its probe twice. GM estimates roughly a 3% defect rate; the remedy inspects and repairs or replaces the engine free and moves to 0W-40 oil. A used 6.2L that's been through the recall is a known quantity; one that hasn't is an open question. Confirm completion by VIN.

Sources: NHTSA complaint database, 2021 Sierra 1500 · NHTSA recall database and manufacturer communications (recall 25V274; transmission-valve coverage; eBoost CSP)

If it's the 5.3L, the lifter issue rides on. DFM can deactivate any of all eight cylinders, and mechanics say its lifters fail more often and earlier than the older AFM — a tick, misfire, power loss, and a $3,000–$10,000 repair with no recall, only a class action and reactive warranty repairs. A DFM disabler (~$150) is cheap prevention and a cold-start tick is the walk-away sign. The 6.2L's risk is largely covered by its recall while the 5.3L's lifter risk is not — factor that into which one you buy.

Sources: NHTSA complaint database, 2021 Sierra 1500 · Independent mechanic transcripts (T1XX Silverado/Sierra; AFM/DFM lifter deep-dives)

The 8-speed can still shudder and shift harshly, but the expensive control-valve failure is covered on this year by GM's 15-year/150,000-mile Special Coverage (from the in-service date, regardless of ownership) — a new valve body free, with reimbursement for prior repairs. The 10-speed on other trims is the stronger unit. Test-drive for shudder and confirm the coverage window. There is a second 2021 transmission program worth checking alongside it: a Customer Satisfaction Program for trucks with the 8-speed (GM's option code MQE) that “may have a broken reaction carrier in the transmission,” where the remedy is to replace the transmission. It is the first federal document tying a 2021 truck's 8-speed to a full replacement rather than a valve body or a fluid change — VIN-check it as well as the control-valve coverage.

Sources: NHTSA recall database and manufacturer communications (recall 25V274; transmission-valve coverage; eBoost CSP) · Independent mechanic transcripts (T1XX Silverado/Sierra; AFM/DFM lifter deep-dives)