Check your front end oil. A friend of mine has the 850 XP his is the shop now getting the clutch paks replaced for the ADC. His front end fluid was black. They upgraded theses parts because they had problems. Check your front fluid at 250 miles change it at 500 miles

 

Mine has always made a groaning noise in ADC when coming down a steep hill. As soon as you let off the throttle all the way and slow to 13 mph the ADC engages, groans and really slows you down.

 

Is the hose from the ADC reservoir to the unit supposed to be filled completly with fluid? My hose has fluid in it almost up to the middle of the radiator area, but the rest of the hose from there to the reservoir is dry. Should this hose be filled completly with fluid, or does the ADC unit prime it as needed? The reservoir is full.

I recently had to have the dealer replace the hose, because it had some fine cracks in it near where it joins up to the unit. Dealer said they had a couple of machines with this same problem. I noticed a slight leak after I first received the machine and when I checked the reservoir, it was dry. According to the manual, your supposed to bleed the front differential unit when you replace the fluid, but I watched the dealer change my hose and I asked him about bleeding and he said that it didn't have to be bleed? Anyone know if this is correct? If it needs to be bleed, I'm wondering if this is why my hose isn't filled up with fluid from one end to the other.

 

My 2009 550 XP just started making the grinding noise on the last ride.The atv has 2600 miles on it.I have the five year warrenty .My 2007 did same thing and dealer replaced the unit at no cost.My atv was just serviced before the ride and the new Plus fluid was used.

 

Sounds like you have an air bubble trapped, it should be full and bubble free to the reservoir.

 

Can I just remove the reservoir cap and squeeze the hose until it fills up, or do I need to get at those two bleed valves? Has anyone done this before? It just doesn't seem like the ADC fluid would bleed out of those valves, looking at where they are located, with relation to the ADC unit and the reservoir??

 

Try and work the bubble up, flip it, wiggle it whatever you can do. As long as you can get the bubble out it shouldn't need bled.

 

I have an 08 sp and mine made the same grinding sound. I followed the manual and bled the air out of the front end. I assume the xp is practically the same. Look for bleeder valve on both sides of the ADC differential. Turn counterclockwise until ADC fluid comes out. get all air out of system by bleeding it. Now do the other side and keep the reservior full. Should solve ur grinding issue. It worked on mine. Tested and fixed