On the oil filter the hole goes out. the metal flat part goes against the spring. On the 04
To check the differential oil in the front pull off the large nut 17mm and it should be up to there on the 04
To check the rear as you are sitting facing the back of the foreman on the left side there is a little bolt 10mm I think and that is the full mark for the rear you should take that bult out and a little oil should run out.
If you just bought the 02 I would suggest to drain and change both differential cases along with the engine oil.
Also if you check out fleet farm in Appleton the may have a honda 450 mantaince book to give you step by step directions for lots of stuff. You might want to check breaks and all the other good stuff. Those book are by the auto repair books
Good luck
To check the differential oil in the front pull off the large nut 17mm and it should be up to there on the 04
To check the rear as you are sitting facing the back of the foreman on the left side there is a little bolt 10mm I think and that is the full mark for the rear you should take that bult out and a little oil should run out.
If you just bought the 02 I would suggest to drain and change both differential cases along with the engine oil.
Also if you check out fleet farm in Appleton the may have a honda 450 mantaince book to give you step by step directions for lots of stuff. You might want to check breaks and all the other good stuff. Those book are by the auto repair books
Good luck