Captive clutch failure in the Ford 6R140 is a chronic problem that is difficult to address with stock components or traditional methods. Key OE parts are not available to the aftermarket, and the clutch assembly is challenging to work with.

Instead of purchasing a new converter or rebuilding a unit with questionable core components, converter rebuilders can restore and extend clutch performance with Sonnax Smart-Tech converter clutch kit FD-CP-20K. The kit’s upgraded components significantly improve 6R140 durability and can be installed using equipment and methods common to the torque converter aftermarket.

Unlike most lockup converters, the 6R140 clutch does not engage the front cover — it moves away from the engine block and engages a stamped, steel backing plate, which is relatively thin and prone to flex. Billet front covers, commonly used to add durability to stock converters, provide no benefit.

Another weak point is the OE clutch, which is held together by a set of small, weak leaf springs. These springs are often broken or on the verge of breaking, causing the OE steel clutch plates to break loose and gouge the cover splines. Clutch failure occurs when damage and debris become severe, a particularly frequent issue in heavy-duty trucks that put massive stress on converter components.

Smart-Tech kit FD-CP-20K replaces the entire captive clutch with unique components that completely bypass the cover splines, allowing even damaged covers to be reused. Assembly and installation are straightforward, and components can be custom fit for proper clutch release clearance to the converter core.

• Optimizes captive clutch performance, even in converters with damaged cover splines
• Straightforward assembly and installation
• High-quality, forged components guarantee better TCC durability and fitment than stock parts
• Rigid backing plate with integrated clutch plate reduces flex and provides a more durable clutch reaction surface than the OE
• Custom coil springs and retainer pins ensure quiet, rattle-free performance
• Extends working height of the front cover lip, minimizing the need to weld a renewal ring to the impeller
• Contains OE friction clutch plate