Sonnax High Capacity 4-5-6 Clutch Apply Piston Kit for 6L80, 6L90

Designed for use with OE-style, 36-tooth friction plates and original-equipment steel plates, the Sonnax 4-5-6 clutch apply piston kit 104960-10K is engineered to resolve common failure points in GM 6L80 and 6L90 transmissions.

Factory clutch assemblies often fail due to insufficient clutch count and limited apply surface area between the piston and clutch pack. Additionally, the OEM backing plate tends to flex or cone under high pressure, which contributes to friction plate failure—especially in performance applications.

The Sonnax kit features a redesigned apply piston and piston dam, along with a specially engineered toothed apply plate. This plate replaces the OE waved plate and allows direct contact with a friction plate to increase surface contact area and distribute pressure more evenly across the clutch pack. By adding one extra OE-thickness friction plate, this kit increases clutch capacity by 17%, making it ideal for builds with higher power output.

• Reinforced backing plate eliminates flex and distortion
• Toothed apply plate improves apply force distribution
• Compatible with OE-style friction and steel plates
• Increases total clutch count to 7 in 6L80 and 8 in 6L90

Note:

OEM frictions are approximately 0.063" thick, and steels are around 0.086". This kit is designed to accommodate one additional friction plate using these dimensions.

Contents:

• Backing Plate
• Apply Plate
• Piston Dam
• Apply Piston

Warning:

This kit is intended for use in vehicles with aftermarket tuning that supports a firmer 4-5-6 clutch apply. Installation in stock vehicles may result in noticeably firmer shift feel due to the increased clutch capacity and removal of the waved plate.

Transmissions: 6L90 (MYD,LY6,6L90E) 2007-UP, 6L80 (MYC,6L80E) 2006-UP

Vehicle

CADILLAC
CTS COUPE, CTS SPORT WAGON 2010-2014 6 SP RWD V8 6.2L
CTS 2007-2014 6 SP R/4WD V8 6.0L
ESCALADE 2007-2016 6 SP R/4WD V8 6.2L
ESCALADE ESV 2008-2016 6 SP R/4WD V8 6.2L
STS 2006-2011 6 SP RWD V8 4.4L
XLR/XLR-V 2006-2009 6 SP RWD V8 4.4L 4.6L
CHEVROLET
SILVERADO 2008-2016 6 SP R/4WD V6 4.3L V8 5.3L 6.2L
SILVERADO HD, CORVETTE 2007-2016 6 SP R/4WD V8 6.0L
SUBURBAN 2500 2006-2013 6 SP R/4WD V8 6.0L
VAN FULL SIZE 3500 2010-2011 6 SP R/4WD V8 4.8L 6.0L 6.6L DIESEL
AVALANCHE 2008-2013 6 SP R/4WD V8 5.3L 6.0L
C-1500 2013-2015 6 SP 4WD V8 5.3L
CAMARO 2009-2015 6 SP RWD V8 6.2L
EXPRESS 2009-2016 6 SP R/4WD V6 4.3L V8 4.8L 5.3L 6.0L 6.6L
SUBURBAN, TAHOE 2008-2016 6 SP R/4WD V6 4.3L V8 5.3L
VAN FULL SIZE 2500 2009-2011 6 SP RWD V8 4.8L 5.3L
GMC
SIERRA 2009-2016 6 SP RWD V8 6.0L 6.2L 6.6L
SIERRA HD 2007-2016 6 SP R/4WD V8 6.0L
SAVANA 2009-2016 6 SP R/4WD V8 4.8L 5.3L 6.0L 6.6L
SIERRA DENALI 2008 6 SP R/4WD V8 6.2L
YUKON 2006-2016 6 SP R/4WD V8 5.3L 6.0L 6.2L
YUKON XL 2008-2016 6 SP R/4WD V8 5.3L 6.2L
HOLDEN
CAPRICE 2012-2016 6 SP RWD V6 3.6L V8 6.0L
COMMODORE 2006-2016 6 SP RWD V6 3.0L 3.6L V8 6.0L 6.2L
SS PERFORMANCE 2013-2016 6 SP RWD V8 6.0L
PONTIAC
G8 2007-2010 6 SP RWD V8 6.0L 6.2L

Alternate Words: transmission and specialty driveline components, 10496010K