you have to pull straight out, no angle at all. If you need a little help you can put light pressure between cv and rear diff. Becareful not to crack diff. Make sure to use plenty of neverseize when re-installing.
What mega said. I use the axle like a slide hammer and get someone to pry between the axle and the case. Should pop out on the first or second pull. Spray some penetrating oil on the shaft where it goes in the diff may help.