I noticed that my 4x4 didn't seem to have the front 2 wheels grabbing, even though the thumbswitch indicated that they were engaged. I set the bike up on jackstands, and sure enough, the front wheels didn't spin. The left one spun once in a while and thenso enemically. I opened up the right one and everything looked ok, with one exception--there was enough oil in there to moisten everything, but there was almost none to spill out on the garage floor. I have manuals on the way, but I was wondering if someone could explain the on-demand system of these bikes, and what may be wrong? Is it just low on oil? What kind does it use? I am hoping it is not something electrical (ie. electro-magnets--that sounds expensive). If you think it is, can you tell me what to do to determine whether or not this is so? Thanks.

 

cant help much,but I have the manual for my 94. The fill plug on the front hub should be about 1/2 way up or down to check level(3 0r 9 oclock) polaris has special fluid for front hubs .Check wires and connections running down to magnets on each hub . Might be bad switch---mine went awhile ago. Goood luck

 

The hubs need a precise amount of oil to function properly, use the polaris hub oil and as mentioned above, it is full when hub is placed at 3(i do two) oclock...

 

Sometimes on the older machines, the neutral safety switch goes on the fritz. It wont tell the circuit board that the tranny is in foward gear. Dont know if this is the case with you or not, but it happend to me. I had to splice a couple of wires together (purple and grey?).
I have found that the best way to test the 4x4 is to get a good strong friend to lift the rear end up, in the stones, and try it.

 

The magnets really arent that expensive from what I remember. I remember being surprised they were not too pricey. And easy to replace. They go out and lose their magnetic qualitys if you leave them in 4 wheel drive like when the bike is stored. Take out of 4x mode when you put the bike up. It's probably not just the oil. Probably magnets (very common)

 

I bought some see through hubs on ebay about 3 years ago ... but now I cannot find anither set for my new polaris anywhere
anyone seen any of these hubs around??

 

Salaman
I’ll try and explain the principle of “on demand 4 wheel drive”.

To make sense of my explanation I am describing two areas of the front wheels.

1. Inner hub
2. Outer hub / wheel assembly
There is a set of drum rollers (5 or 6) that fit into the inner hub in pockets and have a fine wire spring wrapped around them to keep them back in their pockets. (kind of like an elastic wrapped around all five of your fingers.) These pockets are slightly angled…(hard to describe) but the action is like a recoil starter on a lawn mower when the recoil is moving faster than the fly wheel it drives and once the flywheel is moving faster than the recoil it is free…

When the switch is turned on…
Power is applied to the magnetic coil overpowering the fine retainer spring and this pulls the rollers out of their pockets. (tentative locking condition) They are now rolling on the outer hub and this is why you feel a load on the steering when 4 wheel is engaged. It is not locked in this condition.

Now you need to know….on Polaris ATV’s

The front and rear differentials have a different gear ratios. Polaris sets it up so the rear wheels are constantly “under driving” the front wheels (the outer hub / front wheels are rotating faster than the front inner hubs)

When you encounter a slippery situation the rear wheels slip causing the front hubs to rotate faster than the wheels. This, combined with the magnetic pull on the rollers, causes the inner and outer hubs to lock. This condition remains until the front and rear wheels once again rotate at the same speed. (the inner hub once again rotates slower the outer hub / wheel assembly

How sensitive is it?

On a stock Expedition 425 if the rear wheel moves 1/5th of a rotation with out the fronts turning it will engage. It is based on gear ratio and wear…

Wow I’ve understood this for a while but never had to write it down. I’m open for questions if areas seem unclear.

Totun

 

Thanks Tuton, very good explanation!
I believe most of the problems with parts breaking (e.g.: plastic cage) are caused by AWD in reverse. The different gear ratios from front to rear cause the front and rear drives to bind much the same as a 4x4 will bind with different diameter tires from front to rear. AFAIK, the front is geared about 20% lower than the rear and when in reverse the "under-driven" becomes the "over-driven" and actually "over-drives" the rear gear ratio. This may not directly cause the parts to break, but could cause parts to warp, causing the unwanted engagement while the rear wheels are spinning at high speed (apparently this is quite common), causing parts to break. This is just my opinion but I think Polaris is selling these machines thinking that people won't always press the override button and cause this to happen - when traction is good something has to give. You're probably thinking, why would you press the override button if traction is good and you don't need 4wd? The override button also disables the rev limiter in reverse (IMHO should be speed limited instead of rpm limited) and since I have had to press it almost every time I wanted to back up, it has become habit and because the AWD is so seamless in forward, I often forget, or don't care that it's even on until I feel the machine bind. Again, I think the hilliard overrunning clutch is the sweetest 4wd setup out there - going forward, with power applied - just not so good in reverse or when going downhill. That being said, I'd like to see how the front end in the new X2 works.
While we're on the topic, does anyone have an explanation as to why Polaris opted to have such a high reverse gear? It is actually higher than forward low! Maybe if they used a lower gear, they could remove the rpm limiter in reverse. Then, when you pressed the override button, it would be because you WANT AWD in reverse.

 

You hit the nail on the head. At the dunes in april a friend gave his 4x4 scrammy a bunch of gas while stopped ,in 4x4 mode and hitting the override button and his right side transmission case busted instantly.

 

Thanks for all the comments & suggestions. Front hubs are locked but not loaded until the rears slip, right? Sounds very efficient re:fuel consumption. I only now got my hands on some tranny fluid. Being on the Aleutian penensula, nothing is easy to get. They didn't have type "F" but they had type "F-A". Is it going to matter? Why would the hubs be so empty? Is it normal to have to top them off, or should I be looking for new seals? Thore clear hubs sound perfest--woudn't mind finding a set. BTW how clean is clean, inside the hubs? Is it "hospital" clean or "go wipe off the table" clean? Can I hose the hubs and innerds off with brake cleaner, or do you suggest something else? Question regarding the magnets. Why would they go bad, if they, in fact do? Is it the rollers or the coil that goes bad? Or is there more to it? What is the estimated cost of (whichever)? I also need spindle nuts. Mine stake, and the staking tabs are snapping off. Book says to replace with FlexLoc. Who is a (boy, I guess this could be debate) good, reputable parts dealer?