i can feel a vibration in ours that comes up in the driver side floor board at around 25 -30 mph. would that be the same front diff problem that you guys are having? i haven't hear any growling from it but i have not had it in 4wd yet either.
Mine does it too. I'm not sure how the system works, but it probably has a multi-disc clutch or something that kicks in when the rear wheels slip. You don't get 4WD on these until it is needed, so it seems strange when it kicks in. There are alot more driven parts when it is in use. I wouldn't worry about it, but use that feeling as a cue to not let off the gas!!!!!!
My 2013 Jagged X edition XP has the same vibration felt both through the floor and steering. I ride mostly sand, and really notice it hammering down on the loud pedal going up a hill. Not a real encouraging thing to have after spending $20K
A couple of times while going up a steep hill I have had the front differential fail to engage at all. The rear tires will start spinning and loose traction like going up a sand dune hill in 2 wheel drive. Stopping on the hill then starting again will usually let the front dif engage.
I think the growl comes from the fact that the gears in the front end are just straight cut bevel gears instead of spiral bevel gears like you'd see in a automotive ring and pinion set.
Straight cut gears don't have the smoothest/quietest meshing action, and when under load (when the front tires are earning their keep) they just get that much louder.
Mine does it, always has. I'm not worried about it.
After a short drive I noticed mine viberating bad and checked the front drive shaft and I can move it sided to side about an inch and it's not the u-joints. I can see the shaft moving where it goes into the front diff. I have about 1300 miles on it and extended warranty so I will be taking it back tommorrow.