Hi everyone I have a 02 scrambler 400 4x4 that locks into awd sometimes for no reason at all with the awd switch off. It is usaly at high rpm and when slideing sideways and it is usaly the l/f wheel that locks up. I have taken apart both front wheel bearings cleaned and inspected I do not see any problem signs. I also used the polaris fluid when reassembling and it still dose it ???

 

This morning I took it all apart agine removed the axles and washed all the bearings plates and cams reinstalled but not as tight. Thinking mabey to much preload causing them to lock. Then filled with polaris fluid and it still locks at times. Anyone I am realy struggling here.

 

You have a vibration causeing the engagement most likely. I'm guessing one wheel engages suddenly? You most likely have either a warped front shaft or my bet would be a propshaft that has gotten twisted. This happens when the awd is left on and you get some air and when you leave the ground the front wheels slam in gear. Enough times of this happening and the propshaft will twist and cause a vibration and can cause one or both front wheels to lock in or just snap in once in a while. Happened to me. It can be scary when you re at high speeds. Hope this helps. Let us know the outcome.

 

I haven't ever heard that but sounds like it can happen. I would have to go with what polaris would say, that is if you wheels are spinning at 30mph or high no matter what you do the AWD will kick in all by it's self, under cintrifacal force.

 

I did look at where the front wheel drive shaft's connect to the transfer case and there is some free play. I think it is a little excessive but I did not see a spec in the book and I do not have another to compare to.

 

There isn't a spec to i the book. It is possible to be so little of a twist that it may be barely noticable. get a new propshaft first. I hate to say just start putting on parts but there is a good chance that is what it is. The yokes on it are offset for the angle it sits at. I'm not sure the exact angle difference but it's gonna be somewhere around 45 degree offset. (maybe alittle more). If the 2 yokes are close to the same position on the shaft that is gonna be the problem. Too much play where the driveshaft slides onto the front diff can cause issue if the splines get worn but in all but one of the cases I have dealed with the propshaft has fixed the issue. If you have a buddy that is willing to let you swap a part out that would be cool. (just make sure he does not have te same problem first. It gets worse over time.)

 

I think you guys are on to something with the centrifugal force and possibly a little magnetism. The light spring that wraps around the rollers has a spec to it. It did on my Expedition but unfortunately I no longer have the manual. Someone have this spec handy? I believe the spec is "free length" but it might be cheap to replace when you have it apart next. Additionally do you have access to a machine shop demagnetizer? In our tool room we have one. It might also be worth try. Just drag the hub and components over the two coils for 30 seconds...done.

Totun

 

Totun has a good thought. It may fix your problem. But I have tried that on many, even took different springs and tried. I have cut the factory spring and made it tighter. (I have done everything possible to do to the AWD itself that you can name. The hub could be gouged out if it has been doing it for a while but that is an after effect. I would try the propshaft first.

 

there is an armature plate that magnatises off of ground. If you have a wire that is rubbing your frame somewhere this could cause it to go into 4wd. I have seen this a few times when i use to work at a dealer. there should be 2 wire running down the side of the strut. they will be rapped in black plastic.

 

Thanks very much for all the advice. I will check these things friday night or saturday and let you know the out come.