I actually managed to do this from behind just had to remove the luggage tray. I have thin arms and was able to get my arm through the gap to unscrew the orange cap, oil was put with 100ml syringe and plastic tube.
This is a great method, but I couldn't reach my hand through from the top, so I used the following method to change my bevel box oil from underneath:
1. Engaged emergency brake.
2. Placed wheel chocks in front of both front wheels to keep car from moving
http://www.amazon.com/Camco-44414-Wheel-...rds=wheel+chock 3. Raised car by the metal bar in front of the rear wheel using a 2 1/2 ton trolley jack purchased from a local auto parts store (photo attached).
4. Slid RhinoRamp under rear wheel for extra safety
http://www.amazon.com/RhinoGear-11909-Rh...ords=rhino+ramp5. Loosened Drain bolt at bottom rear of bevel box using 15/16" wrench and removed by hand
http://www.amazon.com/Sunex-993030-16-In...=15%2F16+wrench6. Removed orange fill cap by hand
7. Drained old gear oil into a plastic oil drain pan (Edit: I actually lowered the car down from the trolley jack for a bit to get the last bit of oil out with the M3W flat on the ground and then raised it again)
8. Replaced drain bolt by hand and tightened with 15/16" wrench.
9. Added Red Line 80/140 synthetic gear oil to fill hole
http://www.amazon.com/Red-Line-Oil-58104...d+line+80%2F140 using a Plews Pump
http://www.amazon.com/Plews-55001-Lubrim...ywords=oil+pump all the way to the fill hole until some spilled out. Seemed like it took 1/2 to 3/4 of a quart.
10. Replaced the orange fill cap.
Not sure if this is the best or even the correct method, but it was fast and easy for me. The entire process took about 20 minutes on the first try.
