First off if it's been a year and a 1/2 I would go ahead and change it, doesn't cost much and takes hardly no time. You will need 2 bottles of gear oil though. Front takes 8.2 fluid ounces and rear is only around 2.5 to 3 and the gear oil comes in an 8oz. bottle.
Front Diff.- If your sitting on the atv look in from the left hand side at the front diff. You will see a large cap that has a wrench head on it. Unscrew the cap and you can look in with a light and see what your oil looks like. If it's milky then youv'e got water in with it, look for dirt and so on. On the bottom of the diff is you drain bolt. Drain it and fill with new oil up to the bottom of the cap threads. It may not hold the whole amount at first so what I did was filled it up then went and done the rear while the front settled down.
Rear Diff.- Unscrew the cap off the top, then on the left side you'll see a bolt that says right above it, diff oil check or something like that. This is the fill mark bolt, take it out. The i'm not sure if you have to do this but I went ahead and took off the skid plate on the bottom of the diff so I could get the dirt and stuff out that had packed in it. On the right hand side of the diff (I am standing at the back of the quad looking at the diff) at the bottom is the drain bolt. Drain and refill until the oil gets to the check bolt hole and put the sight bolt and cap back on.
After the rear I went to the front diff and was able to put the rest in. Then you done. I done everything in about 30 minutes, no that bad.
Front Diff.- If your sitting on the atv look in from the left hand side at the front diff. You will see a large cap that has a wrench head on it. Unscrew the cap and you can look in with a light and see what your oil looks like. If it's milky then youv'e got water in with it, look for dirt and so on. On the bottom of the diff is you drain bolt. Drain it and fill with new oil up to the bottom of the cap threads. It may not hold the whole amount at first so what I did was filled it up then went and done the rear while the front settled down.
Rear Diff.- Unscrew the cap off the top, then on the left side you'll see a bolt that says right above it, diff oil check or something like that. This is the fill mark bolt, take it out. The i'm not sure if you have to do this but I went ahead and took off the skid plate on the bottom of the diff so I could get the dirt and stuff out that had packed in it. On the right hand side of the diff (I am standing at the back of the quad looking at the diff) at the bottom is the drain bolt. Drain and refill until the oil gets to the check bolt hole and put the sight bolt and cap back on.
After the rear I went to the front diff and was able to put the rest in. Then you done. I done everything in about 30 minutes, no that bad.