Just bought a 2002 Scrambler X 400 4X4 for my son. During his first ride, he noticed a sudden wobble in the front end. I jumped on and sure enough, it was jerking violently while riding. I took it the rest of the way back to the truck and looked everything over while I was riding...looking to see if anything was loose or broken. Saw nothing. Got it home, jacked it up with all 4 tires off the ground, started it up. I noticed that with the AWD selector switch off, the front wheels drive would engage and disengage rythmically...sometimes staying engaged. From what I read in the service manual, with the AWD turned off, the front wheels shouldn't engage, even if the rear wheels have lost traction (which is the case if they're not touching the ground).

So...I figured it was a mechanical problem with the AWD system. I took the left hub off and the roller bearings fell out one by one. There was no fluid in the hub at all. Same story with the strut bearings. Right side was identical. Replaced 8 sets of bearings and races, all seals, cleaned and greased both CVs, replaced both CV boots and clamps, inspected and cleaned both Hilliard clutches (didn't remove the garter spring), serviced hubs with AWD fluid, put it all back together. First test ride...did the same thing. Only this time, it did it after I went from AWD back to 2WD...and it only did it once very briefly. Didn't do it again the rest of the ride.

My questions are...did I just put a band aid on it? Is there something else I should look at? What about stray voltage to the hub? Was it likely that the clutch just needed to be worked back in with new fluid circulating around to lubricate it? Aside from the fact that all these things still needed to be done, was I even close in my assessment on the mechanical problem?

 

Sounds like you found the problem

 

the most important thing besides fluid is those bearings+hilliards have to be preloaded.any play is very bad.i check the hub levels alot considering they only hold ounces.