Is there any way to grease the lower ball joints without pulling the axle shafts?

 

Are they stock? I don't think the stock ones have grease fitting holes. If they are not you should have a plug in the hole. You need to remove it and screw in 45-90* grease fitting. You need to position the u joint between the crosses to gain access. It's a PITA but that's how you do it.