I have a grinding noise in the front end of my sportsman 500.
And the 4x4 doesn't work.

What could be the problem?

 

Year model would help as the early HO had a plain ring and pinion front diff and the awd was in the hubs. Later models had a centralized system with everything in the front diff. Regardless of model have you changed fluid lately?

 

2004 sportsman 500 HO

 

Grinding could be from the hubs as there are plenty of parts that things can happen to. 4 bearings,hilliard assy, armature plate to name the main ones. Try a fluid change first if you haven't already in the hubs and front diff and see if that helps. You may be able to jack up the front end,spin the tires to see if you find the noise in the hubs,prop shaft,axles or even the front diff.. Could be low on fluid or worn and armature plate grinding? Also could be something in the front diff,but that shouldn't cause awd problems usually.The awd ground(brown/white wire) went through the speedo and some could loose grounding there.Plus the thin coil wires to the hubs had a habit on some about loosing ground from the connectors under the front panel.Some have done this to restore awd.

 

Ok thanks I'll look into it tomorrow.

 

I changed the fluid in the diff. And greased the hubs.
Put everything back together now it sounds like plastic is hitting something and it will stop the atv from moving.
What in the hell could that be?????

 

Do you have the AQ model (awd in the front diff) or the one with the awd in the hubs? These have a allen head drain plug in the hubs to drain and fill hub fluid. Both were offered in the 2004 model. Plus grease in the hubs??? Plastic sounding noise could be the drive clutch hitting the clutch cover or could be the plastic roll cage in the front diff if so equipped..

 

The hubs on it are like a trailer hub just a shaft with a big nut.
There isn't hex nuts.

 

Then if you just have the plain hub,the awd is in the front differential,and have a grinding noise,then it could be the plastic roll cage like I mentioned. Here's a video on a Rzr that has the same style diff. Plastic roll cages were the weak point and aluminum cage replacements are available on ebay.

 

All I did was grease the hubs and put it back together.
It was not doing that before I took it apart.