I've got a P reg Fourtrak 2.8 Independent, with the air 4H wheel drive button on the dash, and the 4L on the stick as in all of them. It's got manual hubs, and these seem to be ok, they both turn freely when I go to engage them. I used it for the first time today in 4WD, and it behaved impeccably, but now that it's back in 2WD, I can hear (and feel) an intermittent vibration from the right front wheel. Is it the hub trying to lock back into 4WD mode, or is it another problem. It did do this a few times before I engaged 4WD, so I don't think it's a problem I've caused. It almost feels like driving over some rumble strip, but it lasts for between 5 and 10 seconds then goes away for a while. It only seems to happen when starting from cold, and does not reoccur once warmed up. If it is the hubs, is it easy / doable / economical to change to auto hubs?