I have 30" Zillas front and back. I put on a 3" RDC lift kit this spring and now the 850's which used to be the best mud machine can't go where I go. I love it. No diff issues

 

stock axles? what yr is your machine, 11 or 12? i finaly got the ok for warranty yesterday for my 3rd diff, service manager said has had 3 diffs with busted cases in one month on 900s, never had any all last yr, one guy on here said crown gear looses preload witch would for sure bust a crown gear, crown gear moves away from pinion, poor gear contact, will breaks gears, i put in a forth new diff, witch i bought $1100, so i could stay riding while i waited for the warranty issue, used only the stock tires with this diff and i can move the axles up n down in the diff, alot, after 100 miles with stock tires, looks like crown preload gone again, kinda looks like a diff issue..........i think ill run 30" zillas up front, thanks jack, happy rzring

 

One thing I'd be worried about is actually tire size, might mess the gearing up a bit. I'm 31 outlaws and I have had no problems with my front diff

 

i'll check measurements, just headin to the tire dealer now, taking am silverbacks with to compair, will maybe look at siverback x lites on front too, must be a bad batch a 900 diffs...lol..and i got a few a them

 

Ya sounds like bad diffs. I'm running Rhino axles on the front and stock on the rear. Hope you can get that sorted out. It sucks having your toys in the shop.

 

sure does suck! i also run rhino axles, all 4, didnt do the rears at first, back ordered, and thats when it all started, popped both outer cv cups at full susp droop climing outa a hole, goin back to the truck with front wheel drive, shouldnt be a problem, go slow, couldnt climb a hill, spun a few times, so i backed up the hill, slow as i could, diff dont like that, bent the armature teeth, got new diff under warranty, that one had to be bad, its the one that the grown gear busted and brock the case, didnt make 5 easy miles, first wet spot it broke, drove back to camp 2 wheel drive without spinning a wheel, pretty easy trail i think, polaris is still saying abused, but fixing it after a long fight, 3 rzr 900s in the same shop, same time, same busted diff......hmmm....and they had no diff problems last yr, there is something wrong here