my friend has a 2001 325 magnum and it had been wrecked when he bought it. the front left tire had been pushed back about 1" and that appeared to be the only damage. I decided to check the 4 wheel drive system out the other day after fixing the a-arm damage and the side that was damaged refused to lock up. we replaced the armature plate and cleaned the entire internals of the hub. we checked the magnetic coil to make sure it was magnetising when the switch was turned on and it was working. were running out of ideas fast! the wheel will lock up if you have the entire 4 wheeler off the ground and rev the devil out of. but as soon as you let off the throttle it unlocks again. he said it appears that the last part of the axle is warped a little. any help is appreciated

 

What kind of hub fluid are you using? A lot of people swear by Mobil 1 Synthetic ATF. They say that it is suppose to help with sticky hubs. I plan on switching mine to that.

 

The first thing to check is the hub fluid. Not so much as that is what is wrong, but that it is so easy to do. However, since it was in a wreck, there are other possibilities.

Did you check the magnet pole gap? An accident may have knocked it out of line.
Where the armature plate runs, there will be an inner, and an outer 'sleeve' where the magnet is. The inner sleeve should be as close to dead even with the outer as you can get it (within a couple thousands of an inch) , but not so it sticks out any amount past (you can use a straightedge across the outer, to check). The outer sleeve is movable with a punch & hammer. If it isn't set right, or is crooked, in relation to the inner, gently get it into position with the hammer/punch.
Normally, this doesn't move, but if the machine was involved in an accident, it might be worth checking out.

If all else fails, it could also be caused by the bent axle.

 

yeah we checked the fluid. at first we went with just plain motor oil. he then called the polaris dealer here in town and they said it required a special fluid. he went and bought the fluid and we took the hub back apart, cleaned everything with starting fluid to remove any oil that remained. then we filled it to the level that it called for. no difference. i havent checked the 2 pieces to make sure there flush yet. he did discover that the 6 small bars in the hub were sticking in their carrier. so he filed the recesses until they moved freely.

 

Sounds like you are on the right track. When the hub doesn't lock until it is rapped way out, it is good to check the magnet gap. Also, be sure the 3 little tabs in the armature plate engage the little notches in the cam. If not lined up just right when putting the hub together, it can cause the plate to warp, causing the same sort of trouble.

 

when the gap is correct will you be able to move the armature plate at all when the hub is disassembled and the 4wd system is active? he took the hub off and turned the the 4wd system on with the 4 wheeler running and the transmission in high range and he could move the plate, not real easily but he could move it. hes still leaning toward the warped cv as a possibility.

 

I had a similar problem and it almost drove me nuts. My magnetic gap looked fine with the naked eye, but when I laid a straight edge on it, I found that it wasn't. I was only off by a fraction, but when I lined it up with a piece of wood and a hammer, it worked perfectly.