Go to napa or any other parts store and ask for a "spill free funnel", figure out how to use it by reading the box and think about how you didn't need to jack up your car. Or you could use the curb method if your good at reversing. reverse at an angle on your drive way next to the edge whe...

I just did this yesterday. cut or undo all lines to the rack, rotate rack pinion shaft toward the rear of the car. pull your drivers side rim as if you were taking a sharp right and slide out the rack. if it gets caught on the mounts, slide it back and forth as you work the mount out.