GM 6L80 and 6L90 transmissions often suffer failure of the 4-5-6 clutch assembly due to OE design shortcomings. Not enough clutches and insufficient clutch piston-to-plate apply surface area causes clutch plate failure, especially when apply pressures exceed OE specifications. The other problem is flexing and bowing of the backing plate (coning), which is a primary source of clutch failure.
Sonnax high capacity 4-5-6 clutch apply piston kit 104960-10K features a modified OE clutch apply piston and piston dam that are used in conjunction with a specially-designed toothed apply plate closest to the piston. The Sonnax toothed apply plate increases surface area between the apply piston and first friction plate resulting in more even distribution of apply force to clutch plates and allows a friction plate to run against the apply plate. By eliminating the OE waved plate and adding one additional OE-thickness friction, 4-5-6 clutch capacity is increased by 17%, resulting in a 4-5-6 clutch pack that can handle modified engines with increased power output.

Solid backing plate design outperforms OE and aftermarket plates
Toothed apply plate eliminates waved plate
Use with stock clutches and one additional OE-style friction

More From This Category

PHC Clutch Clutch Kit, PHC Standard, 215 mm x 20T x 23.0 mm, For Abarth 500 2011-2014, 1.4 Ltr I/Cooled Turbo, 312A1.000, 118kw 5 Speed, 11/11-7/14, K

PHC Clutch Clutch Kit, PHC Standard, 215 mm x 20T x 23.0 mm, For Abarth 500 2011-2014, 1.4 Ltr I/Cooled Turbo, 312A1.000, 118kw 5 Speed, 11/11-7/14, K

$745.00

PHC Clutch Clutch Kit, PHC Standard, 215 mm x 21T x 23.8 mm, For Toyota Corolla 2007-2008, 1.8 Ltr DOHC, 2ZR-FE, 100kw ZRE152, 6 Speed, 5/07-11/08, Ki

PHC Clutch Clutch Kit, PHC Standard, 215 mm x 21T x 23.8 mm, For Toyota Corolla 2007-2008, 1.8 Ltr DOHC, 2ZR-FE, 100kw ZRE152, 6 Speed, 5/07-11/08, Ki

$212.93

PHC Clutch Clutch Kit, PHC Standard, 240 mm x 26T x 28.9 mm, Volkswagen LT 2001-on, 2.5 Ltr ICTD, ANJ, 80kw LT35, 6/01, Kit

PHC Clutch Clutch Kit, PHC Standard, 240 mm x 26T x 28.9 mm, Volkswagen LT 2001-on, 2.5 Ltr ICTD, ANJ, 80kw LT35, 6/01, Kit

$1,280.22

PHC Clutch Clutch Kit, PHC Standard, 236 mm x 21T x 29.0 mm, For Toyota Caldina 1997-2002, 2.0 Ltr, 3SGTE, 193kw ST215, 9/97-8/02, Suits Pressed Metal

PHC Clutch Clutch Kit, PHC Standard, 236 mm x 21T x 29.0 mm, For Toyota Caldina 1997-2002, 2.0 Ltr, 3SGTE, 193kw ST215, 9/97-8/02, Suits Pressed Metal

$176.16