Factory build sheet

2021 GMC Sierra Fleet/Base

Build 3GTP8AEF-M · 5.3L 8cyl · Pickup

VIN positions 1 through 8 read 3GTP8AEF and position 10 reads M. Those nine characters define this build. Position 9 and positions 11 through 17 differ on every car.

Every Sierra whose VIN starts 3GTP8AEF and carries M in position 10 left the plant with the same engine, transmission, drivetrain and equipment listed below. We know of 66 of them.

  • Decoded Jul 7, 2026
  • 66 known VINs
  • 1 listed for sale now

Factory specification

As filed by GMC with NHTSA for this build. Fields the filing does not record are left out entirely — a missing row means no recorded value, not a missing feature.

Engine

Displacement
5.3 L
Cylinders
8
Engine model
L82 - DI, ALUM, GEN 5, VAR 1
Fuel type
Gasoline

Drivetrain

Drive type
4x2
Brake system
Hydraulic

Body & chassis

Body class
Pickup
NHTSA body type
TRUCK
Doors
4
Cab type
Crew/Super Crew/Crew Max
Series
1500
Manufacturer
GENERAL MOTORS LLC

Weight rating

GVWR class
Class 2E
GVWR
6,001–7,000 lb

Gross vehicle weight rating is the loaded ceiling set by the manufacturer, not the car's own weight.

The same build, other model years

GMC used the VIN pattern 3GTP8AEF for 3 model years. Nothing but the year changes between these pages, so the price gap between them is depreciation on an identical car.

How this VIN pattern is read

A 17-character VIN carries two kinds of information: what was built, and which one it is. This page is the first kind — the nine highlighted positions.

Positions Characters What they encode
1–3 3GT GENERAL MOTORS LLC · World manufacturer identifier
4–8 P8AEF Model, body style, engine and restraint system
9 × Check digit — computed per vehicle, not part of the build
10 M Model year — 2021
11 × Assembly plant
12–17 ×××××× Production sequence number, unique to each vehicle

66 vehicles carry this build

Every VIN we have decoded to 3GTP8AEF-M shares the specification above.

  • 66 Known VINs
  • 1 Listed for sale now

Neighboring configurations

Other factory configurations of the Sierra, each with its own build sheet. The set is fixed by the VIN patterns themselves, so it does not shuffle as prices or inventory move.

Keep going

Where this data comes from

Specification fields are decoded from the manufacturer's filings in the NHTSA vPIC database, keyed on VIN positions 1–8 and 10. We publish the filed values as they stand and leave out anything the filing does not record.

Vehicle counts come from the 66 VINs of this build we have seen in dealer inventory. They are a sample of the road population, not a production figure.