The Speed Engineering 4L60E to 4L80E transmission adapter harness kit is used to convert a vehicle wired for a 4L60E to run a 4L80E transmission. The kit has two components. The first is an adapter harness that converts the existing transmission plug and wiring to the 4L80E configuration, so no connectors need to be repinned. The second is the input speed sensor (ISS) harness, which runs from the front ISS sensor on the transmission to the ECM and gives the ECM the signal it needs to operate the 4L80E.
Speed Engineering lists the harness as compatible with 1998–2002 Camaro and Firebird, the Pontiac GTO, and GM trucks and SUVs.
⚠️ Important Notes:
- ECM reflash required: the ECM must be flashed with the correct calibration changes for the 4L80E to complete the conversion
- For truck and SUV swaps, only works on 1999–2006 GM trucks and SUVs. Does not work on 2007 and newer applications
- VSS harness wiring: on harnesses with orange and blue wires, orange goes to pin 22 and blue to pin 23. On harnesses with blue and red wires, blue goes to pin 22 and red to pin 23
Features:
- 11-Pin Transmission Adapter Harness: Converts the 4L60E plug to the 4L80E configuration
- Input Speed Sensor (VSS) Harness: Front ISS sensor to ECM
- Braided Cable Loom
- No Connector Repinning Required
Vehicle Applications:
Chevrolet Camaro
- 1998 Chevrolet Camaro — 4L60E to 4L80E
- 1999 Chevrolet Camaro — 4L60E to 4L80E
- 2000 Chevrolet Camaro — 4L60E to 4L80E
- 2001 Chevrolet Camaro — 4L60E to 4L80E
- 2002 Chevrolet Camaro — 4L60E to 4L80E
Pontiac Firebird
- 1998 Pontiac Firebird — 4L60E to 4L80E
- 1999 Pontiac Firebird — 4L60E to 4L80E
- 2000 Pontiac Firebird — 4L60E to 4L80E
- 2001 Pontiac Firebird — 4L60E to 4L80E
- 2002 Pontiac Firebird — 4L60E to 4L80E
Chevrolet Silverado 1500
- 1999 Chevrolet Silverado 1500 — 4L60E to 4L80E
- 2000 Chevrolet Silverado 1500 — 4L60E to 4L80E
- 2001 Chevrolet Silverado 1500 — 4L60E to 4L80E
- 2002 Chevrolet Silverado 1500 — 4L60E to 4L80E
- 2003 Chevrolet Silverado 1500 — 4L60E to 4L80E
- 2004 Chevrolet Silverado 1500 — 4L60E to 4L80E
- 2005 Chevrolet Silverado 1500 — 4L60E to 4L80E
- 2006 Chevrolet Silverado 1500 — 4L60E to 4L80E
Chevrolet Tahoe
- 2000 Chevrolet Tahoe — 4L60E to 4L80E
- 2001 Chevrolet Tahoe — 4L60E to 4L80E
- 2002 Chevrolet Tahoe — 4L60E to 4L80E
- 2003 Chevrolet Tahoe — 4L60E to 4L80E
- 2004 Chevrolet Tahoe — 4L60E to 4L80E
- 2005 Chevrolet Tahoe — 4L60E to 4L80E
- 2006 Chevrolet Tahoe — 4L60E to 4L80E
Chevrolet Suburban 1500
- 2000 Chevrolet Suburban 1500 — 4L60E to 4L80E
- 2001 Chevrolet Suburban 1500 — 4L60E to 4L80E
- 2002 Chevrolet Suburban 1500 — 4L60E to 4L80E
- 2003 Chevrolet Suburban 1500 — 4L60E to 4L80E
- 2004 Chevrolet Suburban 1500 — 4L60E to 4L80E
- 2005 Chevrolet Suburban 1500 — 4L60E to 4L80E
- 2006 Chevrolet Suburban 1500 — 4L60E to 4L80E
Chevrolet Avalanche 1500
- 2002 Chevrolet Avalanche 1500 — 4L60E to 4L80E
- 2003 Chevrolet Avalanche 1500 — 4L60E to 4L80E
- 2004 Chevrolet Avalanche 1500 — 4L60E to 4L80E
- 2005 Chevrolet Avalanche 1500 — 4L60E to 4L80E
- 2006 Chevrolet Avalanche 1500 — 4L60E to 4L80E
GMC Sierra 1500
- 1999 GMC Sierra 1500 — 4L60E to 4L80E
- 2000 GMC Sierra 1500 — 4L60E to 4L80E
- 2001 GMC Sierra 1500 — 4L60E to 4L80E
- 2002 GMC Sierra 1500 — 4L60E to 4L80E
- 2003 GMC Sierra 1500 — 4L60E to 4L80E
- 2004 GMC Sierra 1500 — 4L60E to 4L80E
- 2005 GMC Sierra 1500 — 4L60E to 4L80E
- 2006 GMC Sierra 1500 — 4L60E to 4L80E
GMC Yukon
- 2000 GMC Yukon — 4L60E to 4L80E
- 2001 GMC Yukon — 4L60E to 4L80E
- 2002 GMC Yukon — 4L60E to 4L80E
- 2003 GMC Yukon — 4L60E to 4L80E
- 2004 GMC Yukon — 4L60E to 4L80E
- 2005 GMC Yukon — 4L60E to 4L80E
- 2006 GMC Yukon — 4L60E to 4L80E
GMC Yukon XL 1500
- 2000 GMC Yukon XL 1500 — 4L60E to 4L80E
- 2001 GMC Yukon XL 1500 — 4L60E to 4L80E
- 2002 GMC Yukon XL 1500 — 4L60E to 4L80E
- 2003 GMC Yukon XL 1500 — 4L60E to 4L80E
- 2004 GMC Yukon XL 1500 — 4L60E to 4L80E
- 2005 GMC Yukon XL 1500 — 4L60E to 4L80E
- 2006 GMC Yukon XL 1500 — 4L60E to 4L80E
Cadillac Escalade
- 2002 Cadillac Escalade — 4L60E to 4L80E
- 2003 Cadillac Escalade — 4L60E to 4L80E
- 2004 Cadillac Escalade — 4L60E to 4L80E
- 2005 Cadillac Escalade — 4L60E to 4L80E
- 2006 Cadillac Escalade — 4L60E to 4L80E
Cadillac Escalade ESV
- 2003 Cadillac Escalade ESV — 4L60E to 4L80E
- 2004 Cadillac Escalade ESV — 4L60E to 4L80E
- 2005 Cadillac Escalade ESV — 4L60E to 4L80E
- 2006 Cadillac Escalade ESV — 4L60E to 4L80E
Cadillac Escalade EXT
- 2002 Cadillac Escalade EXT — 4L60E to 4L80E
- 2003 Cadillac Escalade EXT — 4L60E to 4L80E
- 2004 Cadillac Escalade EXT — 4L60E to 4L80E
- 2005 Cadillac Escalade EXT — 4L60E to 4L80E
- 2006 Cadillac Escalade EXT — 4L60E to 4L80E
FAQ
What does this harness kit do?
It adapts a vehicle wired for a 4L60E transmission to run a 4L80E, using an adapter harness for the transmission plug and a separate input speed sensor harness to the ECM.
Do I need to reprogram the ECM?
Yes. The ECM must be flashed with the correct calibration changes for the 4L80E transmission to complete the conversion.
Will this work on a 2007 or newer GM truck?
No. For truck and SUV swaps it only works on 1999–2006 GM trucks and SUVs and does not work on 2007 and newer applications.
Where do the speed sensor wires connect?
If the harness has orange and blue wires, orange goes to pin 22 and blue to pin 23. If it has blue and red wires, blue goes to pin 22 and red to pin 23.
What is included in the kit?
The kit includes an 11-pin transmission adapter harness, an input speed sensor harness, and braided cable loom.
Is this part street legal?
No. Speed Engineering sells this transmission adapter harness as a race-only product intended for competition use only. Installation on a street-driven vehicle may violate the Clean Air Act (42 U.S.C. 7522(a)(3)).
⚠️ Race Use Only: This product is manufactured and sold for installation on vehicles used solely for competition. Once installed, the vehicle may not be used, registered, or licensed for use on a public road or highway. Installation on a street-driven vehicle may violate the Clean Air Act 203(a)(3), 42 U.S.C. 7522(a)(3).
