Chevrolet Silverado HD (2500, 3500; T1XX, 2020–2027)

This doc covers the Silverado HD (2500 HD and 3500 HD pickup and 3500 HD chassis cab). The 4500 HD, 5500 HD and 6500 HD medium-duty trucks (GM515, not T1XX) have their own doc, silverado-md-gm515. NICB's VIN manuals name the Work Truck, Custom, LT, LTZ and High Country trims on the 2500 and 3500 for 2020, and add ZR2 in the 2025 and 2026 columns; the 2025 to 2027 guides print the trim groups 1WT, 1CX, 1LT, 3LT (ZR2), 1LZ and 3LZ. The codes come from GM's fleet order guides (RPO lists, color and trim pages and page-1 trim groups) for 2025, 2026 and 2027 and from the RPO list in the 2023 GM Upfitter electrical body builder manual; the archive also holds the 2020, 2022 and 2024 Silverado 2500 and 3500 HD Upfitter manuals, but this document did not read them, so 2020 to 2022 and 2024 rest on NICB alone. Engines in the lists are the Duramax 6.6L turbo-diesel V8 and gasoline V8s; the 2500 and 3500 HD lists print the Allison 10 speed automatic (2023 and 2025 to 2027), the 2023 Upfitter list also prints a 6L90 6 speed automatic (MYD).

Codes

Engines

Transmissions

Axles

Packages & Trims

Equipment

Paint

Interior Trim

Internal / Process

Sources

Factory documents (T1)

• chevrolet/2025-chevrolet-silverado-2500-hd-retail-and-fleet-fleet-order-guide-rpo-codes.txt — 2025 Chevrolet Silverado 2500 HD Retail and Fleet — GM Fleet Order Guide, RPO Codes — https://www.gmfleetorderguide.com/brand-list/brand/77450ee3-dba7-431a-ad58-098f1ebd9f35/vehicle/22903/model-home
• chevrolet/2025-chevrolet-silverado-3500-hd-cc-fleet-order-guide-rpo-codes.txt — 2025 Chevrolet Silverado 3500 HD CC — GM Fleet Order Guide, RPO Codes — https://www.gmfleetorderguide.com/brand-list/brand/77450ee3-dba7-431a-ad58-098f1ebd9f35/vehicle/22905/model-home
• chevrolet/2025-chevrolet-silverado-3500-hd-retail-and-fleet-fleet-order-guide-rpo-codes.txt — 2025 Chevrolet Silverado 3500 HD Retail and Fleet — GM Fleet Order Guide, RPO Codes — https://www.gmfleetorderguide.com/brand-list/brand/77450ee3-dba7-431a-ad58-098f1ebd9f35/vehicle/22904/model-home
• chevrolet/2026-chevrolet-silverado-2500-hd-retail-and-fleet-fleet-order-guide-rpo-codes.txt — 2026 Chevrolet Silverado 2500 HD Retail and Fleet — GM Fleet Order Guide, RPO Codes — https://www.gmfleetorderguide.com/brand-list/brand/77450ee3-dba7-431a-ad58-098f1ebd9f35/vehicle/23195/model-home
• chevrolet/2026-chevrolet-silverado-3500-hd-cc-fleet-order-guide-rpo-codes.txt — 2026 Chevrolet Silverado 3500 HD CC — GM Fleet Order Guide, RPO Codes — https://www.gmfleetorderguide.com/brand-list/brand/77450ee3-dba7-431a-ad58-098f1ebd9f35/vehicle/23197/model-home
• chevrolet/2026-chevrolet-silverado-3500-hd-retail-and-fleet-fleet-order-guide-rpo-codes.txt — 2026 Chevrolet Silverado 3500 HD Retail and Fleet — GM Fleet Order Guide, RPO Codes — https://www.gmfleetorderguide.com/brand-list/brand/77450ee3-dba7-431a-ad58-098f1ebd9f35/vehicle/23196/model-home
• chevrolet/2027-chevrolet-silverado-2500-hd-retail-and-fleet-fleet-order-guide-rpo-codes.txt — 2027 Chevrolet Silverado 2500 HD Retail and Fleet — GM Fleet Order Guide, RPO Codes — https://www.gmfleetorderguide.com/brand-list/brand/77450ee3-dba7-431a-ad58-098f1ebd9f35/vehicle/23413/model-home
• chevrolet/2027-chevrolet-silverado-3500-hd-cc-fleet-order-guide-rpo-codes.txt — 2027 Chevrolet Silverado 3500 HD CC — GM Fleet Order Guide, RPO Codes — https://www.gmfleetorderguide.com/brand-list/brand/77450ee3-dba7-431a-ad58-098f1ebd9f35/vehicle/23422/model-home
• chevrolet/2027-chevrolet-silverado-3500-hd-retail-and-fleet-fleet-order-guide-rpo-codes.txt — 2027 Chevrolet Silverado 3500 HD Retail and Fleet — GM Fleet Order Guide, RPO Codes — https://www.gmfleetorderguide.com/brand-list/brand/77450ee3-dba7-431a-ad58-098f1ebd9f35/vehicle/23421/model-home
• chevrolet/2023-chevrolet-23silverado-2500-3500hd-electrical-body-builder-sm-en-us-2022oct12.txt — Chevrolet Silverado HD Pickup and Chassis Cab ELECTRICAL section (GM Upfitter), RPO code list pp.9-15 — https://www.gmupfitter.com/wp-content/uploads/2022/10/23Silverado_2500_3500hd_Electrical_Body_Builder_SM_en_US_2022OCT12.pdf
• chevrolet/2025-chevrolet-silverado-2500-hd-retail-and-fleet-fleet-order-guide.txt — 2025 Chevrolet Silverado 2500 HD Retail and Fleet — GM Fleet Order Guide (Print All): page-1 trim groups and COLOR AND TRIM pages
• chevrolet/2025-chevrolet-silverado-3500-hd-retail-and-fleet-fleet-order-guide.txt — 2025 Chevrolet Silverado 3500 HD Retail and Fleet — GM Fleet Order Guide (Print All): page-1 trim groups and COLOR AND TRIM pages
• chevrolet/2025-chevrolet-silverado-3500-hd-cc-fleet-order-guide.txt — 2025 Chevrolet Silverado 3500 HD CC — GM Fleet Order Guide (Print All): page-1 trim groups and COLOR AND TRIM pages
• chevrolet/2026-chevrolet-silverado-2500-hd-retail-and-fleet-fleet-order-guide.txt — 2026 Chevrolet Silverado 2500 HD Retail and Fleet — GM Fleet Order Guide (Print All): page-1 trim groups and COLOR AND TRIM pages
• chevrolet/2026-chevrolet-silverado-3500-hd-retail-and-fleet-fleet-order-guide.txt — 2026 Chevrolet Silverado 3500 HD Retail and Fleet — GM Fleet Order Guide (Print All): page-1 trim groups and COLOR AND TRIM pages
• chevrolet/2026-chevrolet-silverado-3500-hd-cc-fleet-order-guide.txt — 2026 Chevrolet Silverado 3500 HD CC — GM Fleet Order Guide (Print All): page-1 trim groups and COLOR AND TRIM pages
• chevrolet/2027-chevrolet-silverado-2500-hd-retail-and-fleet-fleet-order-guide.txt — 2027 Chevrolet Silverado 2500 HD Retail and Fleet — GM Fleet Order Guide (Print All): page-1 trim groups and COLOR AND TRIM pages
• chevrolet/2027-chevrolet-silverado-3500-hd-retail-and-fleet-fleet-order-guide.txt — 2027 Chevrolet Silverado 3500 HD Retail and Fleet — GM Fleet Order Guide (Print All): page-1 trim groups and COLOR AND TRIM pages
• chevrolet/2027-chevrolet-silverado-3500-hd-cc-fleet-order-guide.txt — 2027 Chevrolet Silverado 3500 HD CC — GM Fleet Order Guide (Print All): page-1 trim groups and COLOR AND TRIM pages

Other sources

• docs/reference/nicb/nicb2020-gm.txt p.165 (2020 Silverado 2500 and 3500: Work Truck, Custom, LT, LTZ, High Country) and docs/reference/nicb/nicb2026-gm.txt pp.151-152 (Silverado HD: Work Truck, Custom, LT, LTZ, High Country, ZR2 on the 2500 and 3500, 2025 and 2026 columns) — NICB VIN manuals
• GM Authority, read through the Firecrawl CLI (gmauthority.com answers direct fetches with HTTP 403) on 2026-10-14, one request at a time and 15 s apart, no block, login wall or CAPTCHA, used to corroborate a sample of codes (T2): "2026 Chevy Silverado 2500 HD Pricing With Options, Packages" (https://gmauthority.com/blog/2025/09/heres-2026-chevy-silverado-2500-hd-pricing-with-options-and-packages/). It agrees with the sampled rows; no row changed. The 2020, 2022 and 2024 Silverado 2500HD/3500HD Upfitter manuals in docs/factory-docs/chevrolet/ (T1, not cited by any row) were also checked for the same sample and agree.
• No other web pages were fetched for this doc. The Silverado fifth-generation doc (docs/rpo/chevrolet/silverado-gen5.md) was read for shared-code wording only.