hey i had a new holland 450 rear mower not to bad of mower , i had to rebuild most of it , it wasnt taken care of very well by previous owner. the sickle stuck on mine also and i used to get pissed, make sure the brackets that attach sickle to the pitman are spread apart you mite have to loosen all the bolts concerning the pitman etc. next do like the other post said a chain or come along hooked to tractor etc and pull ,keep tension on the sickle tight and tap at knife sections rivets or bolts depending on what you have ,keep tapping and pushing ,along with tension and you should be able to get the sickle out.it will move easier as you go, once out clean all dirt etc. out of bar around the guards and hold down clips etc.... then oil the bar before installing sickle back into bar this always helps. i always oiled all my sickles , haybinds and 3pth mowers, even in winter it keeps them ready to go .i hope this helps good luck