4 wheel drive not engaging

[captainjason]

I have a 2018 RAM 4x4, 5.7 Hemi. Took it to the beach for the first time, put in 4x4, and worked just fine. A week later, got to the beach at same location, put in neutral and switched to 4 wheel drive. Got stuck as the front tires won't engage. The light on dash shows it's in 4 wheel (not blinking), but doesn't engage. I am in La Paz, Mexico so trying to diagnose as parts are hard to come by.

 

[chopperman1]

Should be in drive for 4 hi. 4 low requires neutral.

 

[62Blazer]

You don't need to shift the transmission to neutral to go to 4Hi.

The question I have: Sounds like you were at a complete stop, shifted to 4wd, and then tried to take off. Did you get stuck (with just the back tires spinning) immediately after you put the trans back in gear and tried to take off? The reason I ask if that sometimes the entire vehicle has to roll a short distance to get all of the splines lined up and locked before the front tires are spinning. I've seen it several times where somebody gets stuck, they shift into 4wd, and have a hard time actually getting it to engage.
Another question: Are you 100% sure neither front tire is spinning. Make sure you just aren't looking at the driver's side front. With a standard open differential if you get stuck it is quite common for only one of the front tires to be spinning.

 

[Yardbird]

It works best to engage 4 wheel high with the vehicle moving in a straight line.

 

[caulk04]

When it is 'in 4wd', jack up the right front tire and spin it. Look and see if the front driveshaft (diff to t-case) turns when you do that.

If the shaft turns, it's something t-case related. If it doesn't, the front axle is failing to engage.