Chassis package, police conversion

Years 1999, 2006–09, 2014, 2016, 2022–23, 2025–27 Models 8 Factory citations 22

Also described as Police conversion chassis packageSuspension, heavy duty, police-ratedSuspension package, heavy-duty, police-rated

Also documented for Cadillac GMC

Documented applications

Avalanche — GMT900 (2007–2013)

2007–2009 Factory-verified

GM factory document — 2007 chevrolet avalanche 2wd rpo code list, p.1.
GM factory document — 2008 chevrolet avalanche 2wd rpo code list, p.1.
GM factory document — 2009 chevrolet avalanche 2wd rpo code list, p.1.

Suburban — GMT400 (1992–1999)

1999 Factory-verified

GM factory document — 1999 chevrolet chevy suburban 2wd rpo code list, p.1.

Suburban — GMT900 (2007–2014)

2007–2009 Factory-verified

GM factory document — 2007 chevrolet chevy suburban 2wd rpo code list, p.1.
GM factory document — 2008 chevrolet chevy suburban 2wd rpo code list, p.1.
GM factory document — 2009 chevrolet chevy suburban 2wd rpo code list, p.1.

Tahoe — GMT400 (1995–1999)

1999 Factory-verified

GM factory document — 1999 chevrolet tahoe 2wd rpo code list, p.1.

Tahoe — GMT800 (2000–2006)

2006 Factory-verified

The 2006 Tahoe Police Vehicle order-guide pages print it as "Suspension, heavy-duty, police-rated, front, independent torsion bar, and stabilizer bar and rear, multi-link with coil springs"

GM Heritage factory kit — 2006 Chevrolet Tahoe, p.152.

Tahoe — GMT900 (2007–2014)

2007–2009, 2014 Factory-verified

The 2014 Police guide words it as suspension, heavy-duty, police-rated.

GM factory document — 2007 chevrolet tahoe 2wd rpo code list, p.1.
GM factory document — 2008 chevrolet tahoe 2wd rpo code list, p.1.
GM factory document — 2009 chevrolet tahoe 2wd rpo code list, p.1.
GM factory document — 2014 chevrolet tahoe police vehicle fleet order guide wayback, p.4.
GM Heritage factory kit — 2007 Chevrolet Tahoe, p.31, p.191.

Tahoe — K2XX (2015–2020)

2016 Factory-verified

only in: Police Vehicle: S; torsion-bar independent front and multi-link coil rear with stabilizer bar; the lists read chassis package, police conversion; the 2017 shared list also prints it, but no Tahoe page of 2017 or later in the sources does, so 2017 is not claimed

GM factory document — 2016 chevrolet tahoe police vehicle fleet order guide wayback, p.4, p.5.
GM factory document — 2016 chevrolet escalade escalade esv suburban tahoe yukon yukon xl electrical body builders manual service manual 2016 en us, p.19.

Tahoe — T1XX (2021–2027)

2022–2023, 2025–2027 Factory-verified

2027: Police Package: S; printed by the Tahoe police package and special service guides, not by the retail and fleet guides; the body-builder lists read chassis package, police conversion

GM factory document — 2025 chevrolet new tahoe police package and special service fleet order guide, p.7.
GM factory document — 2026 chevrolet tahoe police package and special service fleet order guide, p.7.
GM factory document — 2027 chevrolet tahoe police package and special service fleet order guide, p.7.
GM factory document — 2022 chevrolet 22 suburban tahoe electrical body builder sm u 2021oct08, p.14.
GM factory document — 2023 chevrolet 23 suburban tahoe electrical body builder sm en us 2022sep13, p.14.
GM factory document — 2026 chevrolet suburban tahoe electrical body builder manual service manual 2026 en us, p.11.

This page aggregates every documented appearance of Z56 in the Chevrolet reference. Confidence and citations are shown per application — the same code can be better documented in one year than another.