GM RPO factory option codes

GM records every vehicle's factory equipment as RPO codes — three-character Regular Production Option codes printed on the Service Parts Identification (SPID) label in the glovebox. This reference decodes the most-searched codes across Chevrolet, GMC, Buick and Cadillac: the famous packages (Z71, Z51, 1LE), engines, axle ratios and the G80 locker.

See every code your GM left the factory with.

The CarWhere build sheet decodes any GM VIN into its full factory record — every option code, the original paint, trim and equipment, as built. $9.99, instant.

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Driveline

G80Automatic Locking Rear DifferentialGU6Rear Axle, 3.42 RatioGT4Rear Axle, 3.73 RatioGT5Rear Axle, 4.10 Ratio

Engine

L845.3L V8 (EcoTec3, Dynamic Fuel Management)L876.2L V8 (EcoTec3)L3B2.7L Turbo I4 (TurboMax)LM23.0L Duramax Turbo-Diesel I6LZ03.0L Duramax Turbo-Diesel I6 (updated)L5P6.6L Duramax Turbo-Diesel V8L8T6.6L V8 (gas)LGX3.6L V6LT16.2L V8 (Gen V, naturally aspirated)LT26.2L V8 (Gen V, mid-engine)LT46.2L Supercharged V8

Infotainment

IORInfotainment, base (no navigation)IOSInfotainment with navigationIOTInfotainment, premium with navigation

Performance

Z71Off-Road PackageZR2Extreme Off-Road PackageX31Off-Road Suspension PackageZ51Performance PackageZ06Z06 Performance Package1LETrack Performance PackageZL1Special Performance Package

Suspension & Chassis

Z85Handling/Trailering Suspension

Towing

NHTMax Trailering PackageZ82Trailering Hitch Package

Other brands

Audi & VW PR option codes · Porsche option codes · BMW option codes · Mercedes-Benz option codes

Coverage grows continuously. Codes and names are the manufacturer's published factory designations, assembled from public documentation; applicability varies by market and model year — the authoritative record for a specific car is its factory build sheet. CarWhere is an independent reference, not affiliated with GM RPO.