GM 6L90 (Captive Clutch) torque converters are a nuisance to rebuild. In these converters, the piston is held onto the cover by leaf springs and rivets that are difficult to remove to get to the clutch plate that is captive between the piston and the cover. GM 6L90 diesel-powered applications use a captive clutch torque converter. Sonnax offers performance converter kit GM-RK-22 that does not use a captive clutch plate design thus simplifying rebuilding.

GM 6L90 diesel-powered applications often tow heavy loads which can quickly push the stock two-disc converter clutch past its capacity. Sonnax GM-RK-22 employs a forged 6-pad cover, forged piston and three woven carbon friction elements. Builders now have a dampered 300mm multi-plate option that delivers significantly increased clutch capacity and durability. By re-using the OE damper with the Sonnax clutch plates (bonded with OE woven carbon friction material), GM-RK-22 ensures optimal TCC apply and release characteristics, as well as slip rates that match OE continuous slip calibrations. Drivability is excellent. This easy-to-build and cost-effective kit includes clear, concise instructions.

While testing this kit, Sonnax found that the pressure needed to keep this multi-plate TCC slipping at the calibrated rate was much less than the pressure needed in a comparable single-disc converter. Because the Sonnax multi-plate clutch needs less pressure, there is less demand placed on transmission electronics and hydraulics. With the GM-RK-22, it’s easy for the transmission to keep the TCC slip within required slip parameters.

Enhanced design features include:

• OE friction material bonded to each clutch plate
• Forged components assure rigid apply and reaction surfaces
• Lathe turned feature on mount pads identifies this kit as a multi-plate
• Added clutch capacity reduces required lockup pressure
• Lower operating pressure reduces demand on transmission electronics and hydraulics