This was an excert from the old 500 Magnum article here.

Working in conjunction with the PVT is the "Intelligent On-Demand" true four-wheel-drive system with a right handlebar-mounted on/off thumb switch. Because this feature is a Polaris exclusive and true four-wheel drive is something akin to the Holy Grail for us, we were extremely interested to see if it worked as claimed. The "Intelligent On-Demand" system is designed so that any time the rear wheels slip, both front tires will simultaneously kick in for more traction. One of the best ways to scrutinize front tire traction characteristics is to situate your quad so you're climbing out of a steep creek bed. We found and exceptionally nasty slick and steep stream bank filled with raging waters from Hurricane Floyd. The Magnum could crawl up, stop halfway and then continue; not an easy task. By contrast, the limited-slips on the Suzuki QuadMaster and big-footed Wolverine both required repeated attempts and the use of momentum to crest the bank. The "On-Demand" worked great, producing an odd forward surging sensation in areas that would stop limited-slip machines. Most important to us is the confidence you get knowing you'll have the traction when it's needed.

I had to put this here just for the sake that I hear so many people talk about never seeing a limited slip differential show its 3 wheeling colors. I've done it countless times on my AC. One reason I'm after a Sportsman now. I hear a lot of people say "all four tires are always pulling". Maybe so on level ground, but not in all situations. They never get it. This won't help, but it does give a topic with a little background. If all four are always pulling, then how come the other two quads mentioned here had to rely on momentum and second chances to climb out of this spot?

 

I hope Rooster reads this Andy he thinks he bought a Rubicon that all 4 wheels pull on it. Maybe it will educate him a little on the 3 verse 4 wheel pulling thing. I did also experience the same thing you did Andy on my AC 500 climbing a steep shale creek that had water running down it.

 

One day trying to follow me at Fun Wheeler Park or Larry's Land, and any limited slip owner including a Rancher or Rubi would fully understand the disadvantage of limited slip and a solid rear axel.

Greg

 

Try crossing a creek @ about a 45 angle. Stop when only one front tire has traction. Now gun it. Does the front wheel with traction spin? If yes I say you have true 4wd. Only non-Polaris I saw do that with regularity was a Traxter, I believe.

 

A limited-slip differential is DESIGNED to bias A PORTION of the torque from a spinning wheel to the one with traction. How well does it work? You can find out by jacking up all four wheels, starting 'er in gear, and grabbing a front wheel while you fool with the throttle.

Or, jack up three wheels, weight one front wheel on the ground, and see if it'll pull itself off the jacks.

Remember, a differential by definition divides the power between its two wheels, permitting these wheels to rotate at different velocities. If the device did not perform these functions (i.e., was locked all the time), it would not be a differential.

An open differential has no mechanism to bias torque from a spinning wheel to the one with traction; a limited-slip differential biases a portion of the torque through clutch packs/cams/cones. How much torque is biased depends upon the spring loading of the limited-slip mechanism and the coefficient of friction of the clutch packs (or whatever).

Tree Farmer

 

The fabled Tree Farmer adds a little technical information to the mix! This only aids in supporting the topic. I'm confused as to why there are no disbelievers jumping in here with the mythical super limited slips that go anywhere and beyond.

 

Limited-Slip only slows down the slippage, the fully locked axles are better through mud...the limited slip is good for terrain that needs the atv to turn alot.
I hope I'm right about that...lol

 

Thanks Tree Farmer. That was interesting reading. You ever think of writing for "Hot Rod Magazine", "Ward's Automotive Magazine"? Need references? :0)
Sure you'll never have a problem moving in that direction if you so desire.
Chuck, Suzuki KQ 300, GPS & lunch...

 

Tree Farmer is right on. I researched this subject extensively before I locked up both ends of my truck. I tried limited slips first, there is no comparison. A locker will kill a limited slip when it comes to traction. About the same as a limited slip will kill an open differential for traction. Unless your clutches are completely worn out, your never truly "free wheeling" one side. The clutches are providing some torque to the opposite wheel. When I was pulling against the Sportsman last weekend I was spinning both front wheels equally. But it was on a level gravel parking lot. Plus if you hammer it, the pinion gears in the differential will push the side gears out with much more force. Since the clutch pack is between the carrier housing and the side gears it will engage the clutches more completely. So if you really "stomp on it" you can cause a limited slip to act like a locker for a short time. But then its not always practicle to "stomp on it" for all your traction needs. I don't really know about quad limited slips, but there is alot of difference between the automotive limited slips with respect to traction! Some will damn near work like a locker.

 

Thanks for the kind words, ecorman1, 01Grizzly, and thank you, too, Andy (I think! My post supported and expanded the point you made.).

I don't claim to be an expert; instead, I know how much I DON'T know about differentials.

Many posters don't distinguish between standard ("open") differentials and "limited-slip" differentials, using "limited-slip" as a derogatory term, when they're describing open differential action.

When a differential functions as an open one, with one wheel spinning feely and the other without significant torque applied, many call this condition, "three-wheel" drive. However, the front wheel on the ground provides no driving force to the quad; all the power from the differential goes to the spinning wheel. Thus, when this condition occurs, it might be called "two-wheel" drive, because the only effective driving force to the quad comes from the two spooled rear wheels.

I know, I know, the engine "drives" the spinning wheel; however, since it's spinning, it doesn't drive the quad. Thus, when a front wheel breaks loose, a case can be made for calling this situation "two-wheel" drive, instead of "three-wheel" drive. Call 'em like you see 'em.

Strangely, no one calls SUV's or 4X4 pickup trucks "three-wheel" drive machines, and they have TWO differentials! Jack up two wheels on one side of a SUV or 4X4 pickup, put it in 4WD, and see if it pulls itself off the jacks. Unless some trick is used (like engagement of the ABS as "traction assist," or employment of one or more limited-slip differentials), those vehicles will sit helplessly on the jacks with the elevated wheels spinning. Yet, the same guys condemning "three-wheel drive" quads consider SUV's and 4X4 pickups, "four-wheel drive."

What I wish: I wish some enterprising manufacturer would make automatic lockers for ATV's, like Detroit Lockers. These devices LOCK when sufficient torque is applied to the driveshaft, unlocking at all other times, allowing for easy steering during casual cruising. I assume 01Grizzly's truck has automatic lockers of this type, front and rear (I have an E-Z Locker front and a Detroit Locker rear in my F150 4X4).

This locking action occurs automatically, transparent to the driver. When unlocked, the differential still powers its wheels as with an "open" differential, the locker does not switch back and forth between free-wheeling and powered drive (i.e., engine compression braking is available from all four wheels when the differential is unlocked). Maybe some day . . .

Tree Farmer