Can't seem to get slipper clutch to hold

[Claspers]

Any advice for a dex210. Built the ball diff v v carefully and it runs smoothly. Attached the slipper clutch and finished the build. When testing in the kitchen, all I need is a tiny amount of power and the slipper squeals. Cant seem to get it tight enough to get close to being punchy off the line. Is this normal?