Sounds like you have contamination on the friction surfaces.
Most new pressure plates, and quite often machined flywheels, come with protective oil on them If not thoroughly removed, it will cause what you are describing (called "judder").
Also could be debris on your flywheel or pressure plate if you re-used to old ones w/ out de-glazing or resurfacing them.
You MAY be able to get it really hot (by slipping it as you did) and burning the oil off, but quite often the only cure is to re-replace the clutch plate (since the oil gets INTO the friction material) after degreasing/deglazing the flywheel and pressure plate friction surfaces.
Originally Posted by jfowler
I just put a new clutch in my jeep wrangler 2.5, and when i go to take off it works fine until it gets hot. Then it starts jumping and skipping in first gear. so went to get a new slave and master cylinder for it. Still doing it, so burned the clutch for a second and it stopped doing it. Anyone else ever had this to happen?
By the way if anyone needs a master or slave cylinder or whole thing i've got one