Bent rear flanges are not all that uncommon with larger tires. That's one of the reasons people like TenFactory rear shafts, they cover the flanges while other mfg's don't. Maybe shoot a short video and post it for second opinions.

 

Curious what tire pressure you're running in those KM2s.

 

I was at 35lbs before this issue. I've since adjusted it down to 30lbs.

Ok here's an update on my situation. The bump steer and slight wobble at city speeds has gone away for the most part. I've become more fixated on fixing the pulsating vibes at highway speeds.
I replaced my rear driveshaft last night with an Adams 1310 to try and help with the vibes. No dice. The vibration has changed and increased in the speed of the pulsation tho. It's not quite the same as it was.
Nothing is broken, to my knowledge, and the Jeep has been driving just fine for about 4 weeks since this issue has started. I'm about to just let it go but I also would like to find out what's going on. Any more advice would be appreciated.

 

Thread redone for accuracy and length

 

I had a little vibration after a gear install. Needless to say shop says nothing and it was obvious something was. I believe in this instance the flange is ever so slightly wobbly, cause some driveline vibes- never had this prior to gears. Remove rear shaft, nothing, smooth as butter. I've gotten used to it or it somehow fixed itself but I've no troubles with the gears and that was almost 20k miles ago. Doesn't sound like your problem, but who knows.

 

I'm no expert on DS angles, but with a 4" kit on a 2 dr, you might also need to replace your rear UCA with adjustables to set pinion? I am pretty sure OEM driveshafts are better vibe wise than a double cardan, and that DC shafts are more sensitive to angles.

Otherwise, I had flanges bent myself after some mild wheeling on 34's. You can inspect them by jacking rear end from pumpkin so your tires are just off ground, supporting rear axle on jack stands, chock your front wheels and remove rear wheels, put jeep in drive or 1st gear and let the rear axles spin. My bent rear flanges were bad enough to cause the one side brakes to actually stop that half of the axle due to the rotors swaying in and out of the calipers so much.

 

Pinion angle was checked and is in spec. I'm starting think more and more that my rear flanges are bent.
Luckily I work in a shop so I'll get it on a lift tonight and check them out. What indications should I be on the lookout for, for bent flanges?

 

With the brake assemblies still intact, you will see the rotor moving inboard and outboard if they are bent. If you watch the caliper slide pin area specifically, it will be moving if they are bent. The brake assemblies normall should have no movement if everything is straight and square. If you have a runout dial indicator, you could probably measure it as well.

Here is a https://www.youtube.com/watch?v=vame1AE7eOg with a good clip of a bent flange with lots of play, brake system is a clear sign between the noise and movement

 

I got a video of it last night. The video is of the right side, the left had movement in it as well just not as much

https://www.youtube.com/watch?v=RnEMGdLNidU

 

looks like a bent axle shaft to me.

Replace them in pairs (obviously), most people go with the Ten Factory although I chose the G2 chromoly based on availability and a good deal from my local 4WP.

Ordered mine with new tone rings for the ABS sensors, and new bearings and retainer plates as well. Have the shop press it all together for you if possible.

Couple quick tips for the install;
1) jack one side of axle at a time, to eliminate diff fluid leaking out of the open axle tube on that side
2) you may need to rent a slide hammer to help pull the axle shaft out, mine needed it big time (but I have an 07 in the rust belt). Some guys can get them off by using the rotor itself, installed backwards with the lugs half way screwed in. You might need the little claw attachment also to remove the old bearing race if it sticks inside the housing, we did on one side of mine.
3) do yourself a favour before starting the whole job, check to see if you can loosen the 4x torque nuts that hold your bearing retainers into the axle housing. reason being, they are press fit, and if they spin, you will need to cut them out (and then replace the nuts). Nuts are about $5 a piece, most guys reuse them with loctite but you are supposed to replace them all as they deform when torqued. You will likely need a torch to cut them out, no way to get a grinder in there, maybe a sawzall at best. The nuts are an odd metric size thread pattern, have replacements available or you will not be able to install new shafts (if you had to cut any in the first place)
4) when installing, coat the outside diameter of the bearing race with a thin layer of silicon or maybe even RTV to create a better "gasket" for your diff fluid to stay inside the axle housing
5) torque for the nuts is somewhere around 50 ft lbs IIRC
6) you will probably notice that the brake pad retaining clips on the side with the play will be lacking lubricant from constant "brake action", good time to clean them up + apply some fresh silicon lubricant to the clips, guide pins and backs of pads at same time.

Following the repair, my brakes were noticeably smoother, and some of the vibes I was getting are now gone