Ozzie,
If you are sitting in the tractor seat (facing forward), on my L185 the filter screen is on the left side of the tractor. It is on the side of the tractor. It is behind the foot board of the tractor. It is near the bottom of the side of the transmission. See the second picture of this post and you can barely see it.
The picture is looking down and back from standing in front of the rear wheel on the left side of tractor.
http://www.orangetractortalks.com/forums/showthread.php?t=9299&highlight=filter
Looking on the other side of the tractor (right side if sitting on the seat) you will see a hard line running from the rear of the tractor toward the front of the tractor and going to the pump. At the rear point this line goes into the transmission case. I think it turns into a round fitting about 1.5 inches in diameter. Exactly on the other side of the tractor (on the left side) is the filter port.
What you are looking for is a bump with two bolts holding it on. The screen is behind that. There is an o-ring between the cover and the transmission case. I recall that there is a spring and then the filter screen. The end of the filter screen has a hole in it and you may have to grab it with a needle nose plier to get it out.
I recommend that you get a new screen, O-ring and spring. You will drain all of your fluid when you do this unless you have drained it before you start taking the filter out. You don't want to have to take this apart again for a while due to the cost of the fluids (UDT is ~$100 if I recall correctly).
