I was out on a mild trail one day when this started happening: https://youtu.be/qj3jB1jvCeo
After a few posts on the forums I decided it was most likely the front drive shaft. So I removed the front drive shaft and drove around for a week or so and the noise was gone. I noticed that the front drive shaft rubber boot was gone and it had thrown grease all over the underside of the Jeep. This probably happened a long time ago and it was only a matter of time before it would need to be replaced. So I decided to order a 1350 CV Adams drive shaft. Many probably wonder why the 1350 and not the 1310. I was on the fence about this as well but given the generous discount Adams offered me on the 1350 I decided why the hell not. Many people have the mentality of, "well don't you want the weakest point in your driveline to be the drive shaft because they are easy and cheap to repair/replace?". That is somewhat true but you need to factor the chance of breaking their front drive shaft and having it take out other things as well like the oil pan or transfer case. And I would consider 37" tires borderline between the two.
Between the two videos by JCR Offroad on Youtube and the instructions given by Adams Driveshaft the install was fairly straight forward. I do want to point out a few things that the instructions do not mention and the videos make unclear.
Removing the stock driveshaft is easy and straight forward. I removed the bolts on the front axle side first which allowed me to rotate the driveshaft to get to the eight bolts on the transfer case. To keep the transfer case side from spinning, just pop it into 4 wheel drive.
The flange on the transfer case side popped right off with a few shots from the hammer. The flange on the axle, however, took some serious work to get it to come off. Also, when you remove the flange at the transfer case be prepared for a small amount of oil to drip out.
Installing the new flange at the transfer case goes exactly as show in the existing videos and instructions. I want to point out one thing though, Adams does not recommend re-using the metal/tin flange (on either end) that was on the stock one. It causes more harm than good and can cause an annoying sound. Be sure to torque the flange nut to at least 150lbs and use a bit of red loctite on the threads and the RTV on the nut ... most places recommend 160lbs.
Installing the yoke on the front axle again simple and goes just like the video. However, I would recommend you pushing the yoke on and tightening it down with the impact until it stops. Check and make sure the yoke is seated all the way and there is no play in it. Then remove the nut, apply the loctite and RTV, and then tighten it down. Do not over tighten. This ensures it is on tight and the loctite did not stop or bind the nut prematurely.
With both ends ready, lift the drive shaft into place and install the four bolts that came with it and hand tighten them securing the shaft to the transfer case flange. Then attach the other end to the yoke at the axle. Be sure to check and make sure the top and the button of the joint are pressed all the way into the yoke and they are snug inside the tabs. Do not do this:
Once its in place install the u bolts and evenly tighten them down until its tight but do not over tighten. I then went back to the transfer case bolts and removed one at a time, applied loctite, and then tightened down. I did the entire install with the Jeep on the ground so it required me rolling it back and forward to get to the bolts.
The noise is gone and 4 wheel drive is normal. The driveshaft is an absolute beast and I look forward to, but not really, replacing the rear driveshaft with another from Adams.