[brushlessboy16]

Its not a slipperential persay, but either a slipper or a differential. not both at the same time.

a quote from that same page..

Because so much power and torque from the 550 motors is being delivered to the Team Durango race-winning, shaft-driven, geared-diff drivetrain, our designers have created a slipper clutch which can be transformed into an oil-filled differential. Simply by removing the centre diff locker nut and adding diff gears (available separately), you can control how power is delivered to the drivetrain by fine-tuning the slipper clutch and centre diff.