18U ✓ Factory-verified

GMC · Regular Production Option

Paint, primary exterior, Dark Green Gray Metallic

Years 1999–00 Models 3 Factory citations 4

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Also documented for CadillacChevroletPontiac

Documented applications

Sierra — GMT400 (1988–2000) →

• 1999–2000 ✓ Factory-verified
  ⛭ GM factory document — 1999 gmc gmc c pickup 2wd rpo code list, p.1.

  ⛭ GM factory document — 2000 gmc gmc c pickup 2wd rpo code list, p.1.

Suburban — GMT400 (1992–1999) →

• 1999 ✓ Factory-verified
  ⛭ GM factory document — 1999 gmc gmc suburban 2wd rpo code list, p.1.

Yukon — GMT400 (1992–1999) →

• 1999 ✓ Factory-verified
  ⛭ GM factory document — 1999 gmc yukon 2wd rpo code list, p.1.

This page aggregates every documented appearance of 18U in the GMC reference. Confidence and citations are shown per application — the same code can be better documented in one year than another.