Cooling, auxiliary external transmission oil cooler

Years 1998–09, 2014–20, 2022–27 Models 17 Factory citations 71

Also described as Transmission, heavy duty cooling systemTransmission oil cooler, heavy-duty (auxiliary)Cooling system, transmission, heavy-dutyCooling, external transmission oil cooler, heavy-duty, air-to-oilTransmission oil cooler, external

Also documented for Cadillac Chevrolet Hummer

Documented applications

Sierra — GMT400 (1988–2000)

1998–2000 Factory-verified

GM factory document — 1998 gmc gmc c pickup 2wd rpo code list, p.1.
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.

Sierra — GMT800 (1999–2007)

1999–2007 Factory-verified

GM factory document — 1999 gmc gmc c sierra 2wd rpo code list, p.1.
GM factory document — 2007 gmc sierra classic 2wd rpo code list, p.1.

Sierra — GMT900 (2007–2013)

2009 Factory-verified

GM factory document — 2009 gmc sierra 2wd rpo code list, p.1.

Sierra HD — GMT800 (2001–2007)

2001–2007 Factory-verified

GM factory document — 2001 gmc gmc c sierra 2wd rpo code list, p.1.
GM factory document — 2002 gmc gmc c sierra 2wd rpo code list, p.1.
GM factory document — 2003 gmc gmc c sierra 2wd rpo code list, p.1.
GM factory document — 2004 gmc gmc c sierra 2wd rpo code list, p.1.
GM factory document — 2005 gmc gmc c sierra 2wd rpo code list, p.1.
GM factory document — 2006 gmc gmc c sierra 2wd rpo code list, p.1.
GM factory document — 2007 gmc sierra classic 2wd rpo code list, p.1.

Sierra HD — GMT900 (2007–2014)

2007–2009, 2014 Factory-verified

GM factory document — 2007 gmc sierra 2wd rpo code list, p.1.
GM factory document — 2008 gmc sierra 2wd rpo code list, p.1.
GM factory document — 2009 gmc sierra 2wd rpo code list, p.1.
GM factory document — 2014 gmc sierra 2500hd fleet order guide wayback, p.4.
GM factory document — 2014 gmc sierra 3500hd fleet order guide wayback, p.4.

Sierra HD — K2XX (2015–2019)

2015, 2018–2019 Factory-verified

2015 marks: Sierra, SLE, SLT: S; 2018: GM's 2018 Sierra 2500HD order guide; 2019: GM's 2019 Sierra 3500HD order guide

GM factory document — 2015 gmc sierra 2500hd fleet order guide wayback, p.4.
GM factory document — 2018 gmc sierra 2500hd order guide copy gm authority, p.2.
GM factory document — 2019 gmc sierra 3500hd order guide copy gm authority, p.3.

Sierra HD — T1XX (2020–2027)

2025–2027 Factory-verified

Pro, SLE, SLT, AT4, AT4X, Denali, Denali Ultimate: S

GM factory document — 2025 gmc sierra 2500 hd retail and fleet fleet order guide rpo codes, p.1.
GM factory document — 2026 gmc sierra 2500 hd retail and fleet fleet order guide rpo codes, p.1.
GM factory document — 2027 gmc sierra 2500 hd retail and fleet fleet order guide rpo codes, p.1.
GM factory document — 2025 gmc sierra 2500 hd retail and fleet fleet order guide, p.11.
GM factory document — 2026 gmc sierra 2500 hd retail and fleet fleet order guide, p.10.
GM factory document — 2027 gmc sierra 2500 hd retail and fleet fleet order guide, p.8.

Sierra — K2XX (2014–2019)

2014, 2016–2019 Factory-verified

GM factory document — 2014 gmc sierra 1500 fleet order guide wayback, p.4.
GM factory document — 2016 gmc sierra 1500 fleet order guide wayback, p.4.
GM factory document — 2017 chevrolet sierra silverado electrical body builders manual service manual 2017 en us, p.22.
GM factory document — 2018 gmc sierra 1500 order guide copy gm authority, p.89.
GM factory document — 2019 gmc sierra 1500 limited double cab k2xx order guide copy gm authority, p.40.

Sierra — T1XX (2019–2026)

2019–2020, 2022–2026 Factory-verified

GM factory document — 2019 gmc 19 sierra 1500 body builder feb 20, p.11.
GM factory document — 2020 gmc 20 sierra 1500 electrical body buil 1, p.12.
GM factory document — 2022 gmc 22 sierra 1500 new electrical body builder sm en us 2022jul20, p.12.
GM factory document — 2023 gmc 23 sierra 1500 electrical body builder sm en us 2022oct12, p.12.
GM factory document — 2024 gmc 24 sierra 1500 sm electrical body builder esid 23dec12, p.14.
GM factory document — 2025 gmc my25 sierra 1500 electrical bbm, p.12.
GM factory document — 2025 gmc sierra 1500 retail and fleet fleet order guide rpo codes, p.1.
GM factory document — 2026 gmc sierra 1500 retail and fleet fleet order guide rpo codes, p.1.

Suburban — GMT400 (1992–1999)

1998–1999 Factory-verified

GM factory document — 1998 gmc gmc suburban 2wd rpo code list, p.1.
GM factory document — 1999 gmc gmc suburban 2wd rpo code list, p.1.

Yukon — GMT400 (1992–1999)

1998–1999 Factory-verified

GM factory document — 1998 gmc yukon 2wd rpo code list, p.1.
GM factory document — 1999 gmc yukon 2wd rpo code list, p.1.

Yukon — GMT800 (2000–2006)

2000–2006 Factory-verified

GM factory document — 2000 gmc yukon 2wd rpo code list, p.1.
GM factory document — 2001 gmc yukon 2wd rpo code list, p.1.
GM factory document — 2002 gmc yukon 2wd rpo code list, p.1.
GM factory document — 2003 gmc yukon 2wd rpo code list, p.1.
GM factory document — 2004 gmc yukon 2wd rpo code list, p.1.
GM factory document — 2005 gmc yukon 2wd rpo code list, p.1.
GM factory document — 2006 gmc yukon 2wd rpo code list, p.1.

Yukon — GMT900 (2007–2014)

2007–2009 Factory-verified

GM factory document — 2007 gmc yukon 2wd rpo code list, p.1.
GM factory document — 2009 gmc yukon 2wd rpo code list, p.1.

Yukon — K2XX (2015–2020)

2015–2018 Factory-verified

2015–2018: S on all trims; 2018 from GM's 2018 Yukon order guide

GM factory document — 2015 gmc yukon denali fleet order guide wayback, p.4.
GM factory document — 2016 gmc yukon denali fleet order guide wayback, p.4.
GM factory document — 2017 chevrolet escalade escalade esv suburban tahoe yukon yukon xl electrical body builders manual service manual 2017 en us 1, p.22.
GM factory document — 2018 gmc yukon order guide copy gm authority, p.4.

Yukon — T1XX (2021–2027)

2022–2023, 2025–2027 Factory-verified

2027: S on all trims

GM factory document — 2022 gmc 22 yukon yukon xl electrical body builder sm u 2021oct13, p.11.
GM factory document — 2023 gmc 23 yukon yukon xl electrical body builder sm en us 092822, p.11.
GM factory document — 2025 gmc new yukon denali fleet order guide, p.9.
GM factory document — 2026 gmc yukon denali fleet order guide, p.9.
GM factory document — 2027 gmc yukon fleet order guide, p.9.

Yukon XL — K2XX (2015–2020)

2015–2017 Factory-verified

S on all trims

GM factory document — 2015 gmc yukon xl denali fleet order guide wayback, p.4, p.5.
GM factory document — 2016 gmc yukon xl denali 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.10.
GM factory document — 2017 chevrolet escalade escalade esv suburban tahoe yukon yukon xl electrical body builders manual service manual 2017 en us 1, p.22.

Yukon XL — T1XX (2021–2027)

2022–2023, 2025–2027 Factory-verified

2027: S on all trims

GM factory document — 2022 gmc 22 yukon yukon xl electrical body builder sm u 2021oct13, p.11.
GM factory document — 2023 gmc 23 yukon yukon xl electrical body builder sm en us 092822, p.11.
GM factory document — 2025 gmc new yukon xl denali fleet order guide, p.9.
GM factory document — 2026 gmc yukon xl denali fleet order guide, p.9.
GM factory document — 2027 gmc yukon xl fleet order guide, p.9.

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