Diff. Fluids for front & rear?

check the front drive shaft spline or "U" joint at the transfer case
splines on this shaft wear more quickly that the rear drive line
as the operation angles for the front diff are more acute that the rear shaft

remove the axles --- remove the drive shaft . If it is a Salisbury style diff remove the plate on the front and prise out the diff carrier (Crown wheel assembly ) Undo the pinion nut --remove the pinion and pull the pinion out the front. If it is a centre that is bolted in from the back then undo all the bolts around the cast housing and pull of that way.

wd diff lock only locks the front to rear diffs not the 2 wheels on the same diff. To have both front wheels driving as you require will need limited slip diff in front or locker in front Be hard to steer in tight areas but they are available.

make sure your hubs are locked. the auto-hubs should be checked too for extreme wear.(if equipped) next look at the diff are all the gears there and not f'd up.put trans case in N and rotate front shaft, full turn with no resistance with hubs locked means diff problems. if shaft rotates in gear(any but N) and wheels off the ground, you have a Tcase problem(chain, shift linkage). so theres some things to think about.

on a 2wd drive on the trans on a 4wd its on the transfer case if its for the abs each front wheel has its own and the center of the rear diff

the acutator on the front diff. might not be working even though its engaging in the trans for the gear ratio it still sounds like its not engaging in the front diff.

if it has a spring between the side gears , it may be a limited slip diff center and the noise may have been the limited slip action coming off or engaging when one front wheel lost traction
if there is no metal bits in the diff then it may be nothing as long as both wheels turn the diff center , then the axle will still be intact

if the leak is from the rear portion of the diff, often it can be cured by removing the cover, cleaning the mating surfaces, resealing and reinstalling. if the cover seems to have excessive corrosion inside, replace it. they are relatively inexpensive and available at almost any parts store, but original dodge ones from the dealer fit the best.

if the leak is from the front portion of the diff (front seal), this requires a some work beyond the scope of most home mechanics, but is not usually a very expensive job. good luck!

Howdy, My name is Mark, I am a mechanic (Auto trans and Diff specialist 23 years) this symptom is common with a broken driveline component, with full time 4WD and centre diff all the drive goes to the wheel with least resistance, (or to broken component) therefore when you engage difflock (Center) the drive then goes 2 ways front and rear so vehicle will drive, could be as simple as stripped spline in front wheel hub, broken CV joint etc. 1 major weakness these vehicles have is if driven with center diff lock engaged on high traction surfaces they do break the front diff, this will give the same symptom but you would of been aware of it when it happened.
To check where the drive is going chock all 4 wheels, park brake on, bonnet up, start engine let it idle down (after cold start), engage reverse (high range open center) from the front of vehicle and off to one side you can see the front axles, if one of them is turning that is where your drive is going, have someone to help you and under no circumstances place your self under or in driving path of vehicle.
Hope this helps

The button is to lock the central diff to distribute the power 50/50 front to rear when in slippery conditions,
Normally with button off the drive system favours the front wheels.