whining when 4wd is engaged

Hi all,

had to engage 4wd due to snow and when i did there was a terrible whine coming from the front end of my truck. Its fine in 2wd, but when i engage 4wd and lift the clutch, the whine starts, dip the clutch and it goes. Any ideas? My first guess is the vacuum hubs have gone as it doesn't sound like its coming from the clutch or the transfer box, it sound like its coming from the axle.

Obviously if its the hubs, ill be swopping them for manual lockers, but is it likely to be owt else?

Well you mentioned and ruled out transfer box whine but thats all I hear when I'm in 4wd, in particular when in 4L. Dont suppose this helps though lol.

I get whine in 4L too, as far as i know its normal

Nothing in 4H

Its more of a grinding whine, rather than transmission wind up - its difficult to describe but its almost as if something rubbing somewhere, which makes me think its the hubs not locking in properly