Roll the vehicle slowly forward or back and the tcase should click gently into engagement. A little bit of movement should allow the gears to align.

Is your Jeep automatic or manual?
If you have the engine running, what gear are you in?

 

12+ years of the NP241 or NV241OR & only a small % of operators ever come to grasp the simple-finesse of rolling into or out of 4L ,4H,N, or 2H on these things.
It is explained so clearly in user manual & above ,by @ExWrench.
Admittedly, it takes once or twice but is unintuitive.

I've always thought that all of the broken ,eclip, xfer case shifter breaks were at least partly from folks engaging the transfer case too aggressively because of the simple minute movement needed to get it into 4.

 

I'd recommend not putting any more than about 5lb of force on the shifter. Sounds like you may be stopped and in neutral; if so, have someone push the jeep from behind while you're gently nudging the shifter into a gear. If you can't do that, you could lift the front and rear tires off the ground and spin the driveshaft(s) by hand a little. If you end up breaking the cable ends, Advance Adapters makes a nice replacement with little steel heim joints instead of the cheap plastic, but it's still no excuse for moving the lever gently. My original cable never failed me when out and about, but when I disconnected it for another project (11 year-old jeep), the plastic ends basically disintegrated in my hands. Good luck!

 

Thanks guys, I tried that but maybe didn't roll the jeep enough.
It doesn't do that if I just put in 4 wheel drive for driving, just after towing it.

 

After towing our JK for the trip quite often the t-case does not want to gently come out of neutral. I start the engine and immediately shut it off. As the gears spin down it will slide into gear w/o grinding. Sometimes I have to do it twice. The joys of the manual t-case & auto transmission.

 

.... The joys of the manual t-case & auto transmission..

^ that's the best , most-accurate way that I've heard this (extremely) common occurrence described.

 

Buy a Prius. You don’t need a Jeep.

 

I dunno, man. I imagine OP would have even greater difficulty shifting one of those into 4Lo