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GMC Sierra 1500 2nd Generation (GMT800)

1999–2006 · GMT800 · truck

The GMT800 Sierra launched for 1999 as the first truck wearing the Sierra nameplate, replacing the GMC C/K. Mechanically identical to the Silverado GMT800, with the same 4.3L Vortec V6, 4.8L LR4, 5.3L LM7, and 6.0L LQ4 V8s, all Gen III small-block iron-block Vortec engines. No AFM in this generation. The Sierra-only Denali trim debuted on the GMT800 with the C3/Denali AWD variant introducing all-wheel drive on a full-size half-ton.

Watch out: Rust on cab corners, rocker panels, and rear wheel arches in salt-belt states. Owner reports of intake manifold gasket leaks on 5.3L LM7 and 4L60E transmission wear at higher mileage.

What your Sierra 1500 takes

The parts and fluids that fit this generation. Specs we publish are confirmed against two independent sources; the rest fill in as we verify them.

  • Tire size235/75R16✓ VerifiedView
  • BatteryGroup 78 · 690 CCA min✓ VerifiedView
  • Oil filterParts in catalogShop
  • Brake rotorsParts in catalogShop
  • Wiper bladesNot catalogued yetFind yours soon
  • Engine oilNot catalogued yetFind yours soon
  • Engine air filterNot catalogued yetFind yours
  • Cabin air filterNot catalogued yetFind yours
  • Spark plugsNot catalogued yetFind yours soon
  • Headlight bulbsNot catalogued yetFind yours soon
  • CoolantNot catalogued yetFind yours soon
  • Brake fluidNot catalogued yetFind yours soon
  • Transmission fluidNot catalogued yetFind yours soon
  • Tire pressureNot catalogued yetFind yours soon
  • Key fob batteryNot catalogued yetFind yours soon
  • Power steering fluidNot catalogued yetFind yours soon
  • Differential fluidNot catalogued yetFind yours soon
  • Serpentine beltNot catalogued yetFind yours soon
  • Brake padsNot catalogued yetFind yours soon
  • Wheel fitmentNot catalogued yetFind yours soon
  • ThermostatNot catalogued yetFind yours soon
  • A/C refrigerantNot catalogued yetFind yours soon
  • Fuel filterNot catalogued yetFind yours soon

Full clubhouse — owner Garage Lineage, common problems, year-by-year notes, and product picks — is on the build list.

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