Failure mode - GM 3.0L Duramax LM2/LZ0 I6 (2020+)
LZ0 crankshaft thrust bearing failure (GM bulletin 25-NA-307)
Reliability tier: aggregated - verify before ordering, see /disclosure/
Symptoms
- noise from the bellhousing area, oil-pressure code P06DD, 'Reduced acceleration' message
- sudden engine failure at low mileage (owners report failures under 12,000 miles); engine replacement under warranty with long waits
Compare with the other causes of the same sign on this engine: loss of power, limp mode or derate (7 causes) · ticking, knocking, rattle or whine
Root cause
On LZ0 engines, mostly MY2025, the crankshaft thrust bearing fails and lets the crankshaft move fore and aft; the damage can destroy the engine. GM technical service bulletin 25-NA-307 (1 October 2025; 2025-2026 Silverado/Sierra/Tahoe/Suburban/Yukon with the LZ0) gives dealers inspection steps: bellhousing-area noise, P06DD, crankshaft end-play measurement, bearing repair. No safety recall at NHTSA (checked 25.10). NHTSA: 30 of 1,190 VIN-confirmed 3.0 diesel complaints name the thrust bearing, 26 of them MY2025. Root cause is disputed in the trade press.
Diagnosis
- ask whether bulletin 25-NA-307 was performed; bulletins do not notify owners
- listen for bellhousing-area noise and read stored codes (P06DD)
- a dealer measures crankshaft end play per the bulletin
Fixes
dealer inspection and thrust bearing repair per TSB 25-NA-307; engine replacement under warranty when damaged ()
Prevalence
occasional