Its been a while since I have done this, but you need to remove your cable to grease or replace, either way. What I can’t remember is if the cable itself can be pulled through the casing once it is removed due to the squared off ends. If it does come through, don’t pull it all the way out. Pull it out a bit, grease cable and push it back in. Repeat process each time pulling it out a bit further grease and push it back in till the cable rotates freely in the casing.