My rear passenger door lock is very tough to lock and unlock by hand. The remote lock system cannot lock or unlock it either. Before I rip the door report has anyone had this issue before? Could it just be a matter of some grease?

 

Would like to know the same thing,have the same problem on my passenger door.

 

Same here, although it's easy to do manually.
I would love to see some pics of the door apart.

 

Thanks for your help. Wound up taking it to the dealership and it was covered. Needed a new locking mechanism.

 

The door actuator's in the JK's are sh*t. If you're having door locking problems, 9 times out of 10 the actuator has failed in some manor. I've replaced 2 actuators in mine. Driver's front and driver's side rear doors both had the same failing actuator problem and needed the actuator's replaced. The 1st one was the front and the dealer replaced that under warranty. I found out recently when they replaced the front, they cracked the "Latch presenter" which is a plastic POS bracket the actuator attaches. I had to replace that a couple years later since my door stopped opening from the inside. I replaced the rear passenger door actuator last week.

When I ordered the replacement actuator, I noticed the replacement P/N had been revised multiple times from my factory part. So Jeep knows these things are junk and have likely tried to improve them, thus the reason for the multi revised part number.

If you do this repair yourself, my best advise is that you will want to disconnect the Window from the channel slide and tape the window so it is held in the upright position. After you do that, then the door is easier to disassemble and access the actuators that need to be replaced.

If you want to see the door apart, watch this video. It's the best one I found which shows most of the steps that will need to be done to replace the actuator. Taking the window in and out is actually pretty difficult, and not as easy as it shows was done in the video. So that's why I advise to unfasten the window and tape it in the upright position instead.
https://www.youtube.com/watch?v=iQGI8UWG8s0 Post any questions you might have, I've had my doors apart multiple times diagnosing and repairing these actuators so I've kind of have unwillingly become an expert on taking the doors apart.