Mercedes-AMG 725 9G Spool FX-RT Upgraded Transmission Clutch Kit

The Spool FX-RT upgraded clutch kit for the Mercedes 725 9G transmission raises clutch-limited torque capacity to about 1,700 Nm for high-power AMG builds.

Why you need it

The 725 9G is strong from the factory, but past the mid-700 Nm range the stock frictions start to slip under repeated high load and heat. Spool's FX-RT friction material, proven in its 8HP50 kits, adds about 20% more friction coefficient, and the kit increases the plate count in all six clutch packs. Together that lifts torque capacity by 68% to 71% depending on gear, from a factory rating of 1,000 Nm.

Fits

• Mercedes-AMG models with the 725 9G transmission, including high-power M177 builds, GLE63, GLS63, E63 and S63

Features

• FX-RT high-coefficient, high-energy friction material
• Higher plate counts in clutches A through F
• About 1,680 Nm clutch-limited rating in 1st to 4th and about 1,714 Nm in 5th to 9th
• Better thermal stability and less shift flare and slip
• Works with factory drums, pistons and snap-ring locations

What's included

• Clutch A pack: 6 FX-RT frictions, 6 upgraded steels, custom pressure plate
• Clutch B pack: 7 FX-RT frictions, 7 steels, custom pressure plate
• Clutch C pack: 7 FX-RT frictions, 7 steels, custom pressure plate
• Clutch D pack: 9 internal and 9 external spline FX-RT discs, custom pressure plate
• Clutch E pack: 9 FX-RT frictions, 9 steels, custom pressure plate
• Clutch F pack: 10 FX-RT frictions, 10 steels, custom pressure plate

Good to know

Each clutch pack comes pre-measured and packaged for consistent clearances, with no machining needed. This is a transmission rebuild part and should be installed by an experienced transmission builder.