Where do I drain the hydraulic oil?

On the 270D, the hydraulic reservoir sits behind/below the operator's seat on the right side of the chassis, same layout as the 250/260/270 series. Most Deere skid steers this era have a drain plug on the bottom of the hydraulic tank itself, accessible from underneath the machine, plus a separate drain on the hydraulic filter housing/base.

Procedure:

1. Run the machine to operating temp first, warm oil drains faster and carries more contaminant out with it. Then shut down and let pressure bleed off, cycle the controls a few times with the engine off to relieve any residual pressure in the lines before you open anything.
2. Raise and block the machine or tilt the cab/rear door for access underneath, depending on your access door configuration, some D-series have a bottom skid plate that needs to come off first.
3. Locate the tank drain plug on the underside of the reservoir. Pull it and let the tank fully drain into a catch pan, this takes a while since it drains slowly through a small port.
4. While it's draining, pull the hydraulic filter and let the filter housing drain too, that housing holds a few extra quarts that won't come out through the tank plug alone.
5. Check the suction screen inside the tank (accessible once drained, usually under a cover plate on top of the tank) for debris while it's open, this is a common spot to find metal fines if a pump is wearing.
6. Refill through the fill neck on top of the tank with Deere HY-GARD (or equivalent) to the sight gauge level with all cylinders retracted, then cycle every function several times to purge air before topping off again.

Exact capacity and torque on the drain plug varies by whether you've got standard or high-flow auxiliary hydraulics, the parts/technical manual for your PIN range will list it. If you want, post whether you've got the standard-flow or high-flow package and I can narrow down the exact drain and refill points.