I’m trying to make a slider and i want to add a controler to it so when i rotate the controler (empty) the slider opens or closes. But i also want to controler to only rotate on the z axis from 0 to 2.75 degrees, and to not rotate on the x or y axis. is this possible? If not can i make it so when i rotate the controler there is a min/max position for my slider?
Im sorry noone has answered your question, me1. I think using an armature bone might suit you better. You can lock an axis like an empty, but you can also set rotation limits, too 
In Pose Mode, select the control bone and press Ctrl-I, and choose ‘without target’. Now you can set rotation limits or locks on each axis.
You can lock rotation on specific axes, but you can’t limit rotation/translation/scaling yet!
What sort of setup are you going for here? A setup where the slider is a 3d object that moves like a door, or a setup where the slider and controller are two ways to control one thing?
Aligorith