Changing the front and rear diff fluids (2006 Foreman)

[MudMan]

I'm not the master mechanic by any means so forgive me if this is a stupid question (and probably is).  I have a 2006 Honda Foreman 4x4 with about 600 miles on it.  All I've ever done to it is change the oil.  I would like to change the front and rear diff fluids but have no idea how to or how complicated or how easy it is. 

Any help would be appreciated.  Also, how often should you change it ?   And what other simple maintenance needs to be done on this bike ? I haven't had it that long.  I want to keep it running good. 

[Mars]

First pull the level check plugs. If it's full and clean leave it.If not:
 Drop the skid guards and you will see 2~3 plugs. (fill/level/drain). On most front diffs the bottom of the fill plug is "full". You need a qt of limited slip lube 75w90. Check your manual. Ride the bike a few miles to warm up the lube. Drain, fill to level, snug up all plugs. (soft alloy, go easy)

[Fox17]

Get some Pro Honda hypoid gear oil first. You dont need much. Then, there is a level check, a fill hole, and a drain plug.

On the back, drain it if its dirty, put that plug back in, and then take the level check bolt out and fill it up until oil comes out that and then hurry and put the level check bolt back in.

On the front, if it looks dorty, drain it via the drain bolt. Then put that back in and fill it so its level with the bottom of the filler hole.

The filler holes are the big 17mm bolts on the top. I think the drain and check bolts are 10mm. Drain is the bottom and check is on the side. They might be labeled on the differentials. They are on some Hondas. Ill get pics if I can get the camera working and ill post them.