[Tony Radford]

Sounds like you don't have enough travel to fully disengage the clutch (been there). I'm running a long throw Ram and I eventually replaced my master with a longer throw unit. My suggestion is that you ajust your mechanics so that it fully disengages the clutch even if it starts slipping under load. If you can do that, you will have confirmed that you simply need more travel. It's not the easiest issue to resolve, but at least you'll know what to concentrate on.