Please help with Front End Grinding 09 850XP

I have searched the forums and cant find my specific issue.

I recently noticed grinding, like gears grinding, coming from the front end of my 09 850XP browning. I have 7000 miles on the bike and have used the ADC only once or twice. This all happens whether the bike is in AWD or in 2WD. I have not tried it in ADC mode, I don't use ADC.

The grinding only occurs when hitting the gas from a dead stop or when applying strong throttle while in deep mud. It sounds like gears grinding.

I pulled the front end and found nothing but dark sludge for fluid. I cleaned all the parts and the main gears look fine, no missing or broken teeth, and the clutch packs all looked good (no metal on metal). I replaced all the bearings and seals and replaced the plastic cage with an all aluminum cage.

I also replaced both front axles, I know it is not a CV joint slipping.

I also noticed the ADC fluid was dark and flushed the system. I followed the shop manual and bleed the ADC fluid until clear fluid with no bubbles was seen.

Put the front end back in the bike and the problem seems to have lessened. The bike does not grind when in mud but still grinds when hitting the gas hard, from a dead stop.

This all happens whether the bike is in AWD or in 2WD. I have not tried it in ADC mode, I don't use ADC.

 

Some people have had to flush fluid several times especially if they haven't changed the fluid often enough and the fluid is dark. Grinding is probably shudder or chatter from the clutch packs. Addition running/ flushes may help on the noise,if it doesn't, clutch packs may need to be replaced even though they may look okay. LT fluid didn't help matters on the early ones,not sure if the Demand Drive Plus solves all the problems when they went to just one fluid.

 

I pulled the front end out of the bike and took the clutch packs apart. the clutch material looks good. put the packs back together and re-seated the new bearings. The fluid looked good but still had a little tint to it.

reinstalled the front end and replaced fluid and again bleed the ADC. I still have grinding, although it does not seem to be as bad. It only does it when the throttle is nailed from a dead stop. my real concern is why does it do this when it is in 2wd or 4wd. The ADC should not be engaged when the bike is in 2WD. If I understand the principle concerning ADC, the ADC should not engage unless the switch is set to ADC and the bike is at less the 15mph. I dont understand why the fluid would cause this when the bike is in 2wd?? The AWD system works fine. It goes in an out of AWD with the push of the button, no issues with AWD working or with all four wheels pulling when in AWD mode.

Old Polaris Tech, am I missing something??

 

No your probably not missing anything,but the ADC works on the same principle as the AWD. AWD is not supposed to engage when power is not going to either the diff on the centralized systems or the front hubs on the older models,but they can since voltage is just one part of the system,mechanical action is the other,and that is what I believe is the problem you're having.Maybe some of the others that have the ADC have found a better solution to this,or even a better fluid or even an additive to quieten clutch pack noise/shudder like they have for automatic transmissions on cars,but so happens when all this really started happening I was already retired and out the door. Hopefully others can jump in on this one to help.

 

I have changed the fluid 3 times now and bleed the adc each time. This weekend I have now picked up a popping sound when driving slow. I can feel the pop through the handle bars and can hear it.

I fairly sure I have a front wheel bearing that is bad and may explain the new popping noise.

However, the front grind is not getting any better. it does not grind if I am moving and nail the throttle but if I am sitting still and hit the throttle hard the grind is awful. It almost sounds like the grind that occurs if you try to put a Polaris in gear when the RPM's are too high.

I am going to pull the front drive shaft out of the bike this week and see if I still get the grinding noise. maybe I can isolate the noise and ensure it is, in fact, coming from the front end. I rebuilt the transmission last year and cant imagine it is the transmission, but with this 850XP nothing would surprise me. if it is the front ADC giving me the problems, I am going to cut the ADC power wire and remove the ADC system and CAM.

Any other suggestions will be GREATLY appreciated.

 

Only thing I can say is re inspect the clutch packs and internal parts for anything you may have over looked.

 

You sure its not the coupler in the tranny? the 09's have a coupler on the tranny output that strips, there is an eliminator kit , I think high lifter makes it, Polaris eliminated it on later models, I haven't had one apart yet but have heard of others having to do it. Just looked it up , Cycle parts warehouse Under 850 , Drive Train Main Gearcase-A09ZN858X-all options #25 part # 5136575 $83.70