OK boys and girls sorry no pictures for this post. But hopefully useful. I wanted to have a resolution to the issue before posting this series of events.
After the install of the 241 I had the slightest rumble in the steering wheel between 28-38 mph. Not a vibration, an audible rumble that was felt in the steering wheel and shifter, and mind you it was slight, but noticeable. At first Blaine thought it was the tires. I have some minor cupping on the front tires because well... MTRs. So first we had to eliminate that possibility. I was skeptical it was tires because I didn't have any rumble before the 241 and new Tom Wood's shafts but there is some noticeable cupping and I have the utmost trust in Blaine so the first step was a rotation and balance to try and eliminate that possibility. Easiest first. After the rotation and balance it was a little better but still there. Then I went for an hour long drive on the freeway and the problem progressed to a significant rumble that shook the seats and mirrors between 28-38 and then 55-70. So next I removed the front drive shaft and the rumble was still there. Next, after reinstalling the front drive shaft, I went to remove the rear drive shaft and I noticed I had developed quite the leak at the rear flange nut. Noted. I removed the rear drive shaft and drove in 4 high. No rumble. It drove smooth as silk. Ok, so I installed my other(spare) rear drive shaft. Same rumble. Ok not the drive shaft. I pulled the rear drive shaft again and at Blaine's recommendation I was going to seal the leak at the rear flange nut with RTV. The red locktight on the rear output shaft had not been disturbed and was on the tip of the shaft AND the top of the rear flange nut. So I got my 1 1/8 socket and breaker bar and went to loosen the nut. The nut was on just barely past finger tight, I almost launched the breaker bar thinking it was going to be torqued! Ok, that's weird. I had been driving around with a more or less loose rear flange nut. I removed the nut, put high temp RTV on the bottom and torqued it down and reinstalled the rear drive shaft. After a test drive the rumble was still there, and the highway speed rumble had changed to a vibration. To confirm my findings I pulled the rear drive shaft again and test drove in 4 high. No rumble, no vibration. After consult with Blaine, next step was to test a different transfer case.
Quick backstory if you're so inclined to strap in. After a few trips to the rocks with my newly modified rig, I quickly realized I personally wanted a better crawl ratio. Blaine and I discussed the different ways to achieve this and with the size and prices being what they were for used 241's, an Atlas was the best option. I wanted a 241 because, well, I am me and I don't like to disturb the factory look of the interior too much and I like the stock shift lever. But, after talking more with Blaine and
@Alex01 I had mentally convinced myself the performance of the Atlas will distract from my non-stock shifters lol. Blaine understands there are many different types of jeep owners and I personally think he likes a challenge, and he found me a 241 at a more than reasonable price. But there were stipulations to him installing a used 241 into my jeep. He needed to have the ability to replace it. That means he needed to have another on hand in case the one being installed in my rig shits the bed. This is not only a sound business practice, but one that I highly respect because it means he won't do something to someones rig that he can't fix or replace if something goes wrong.
So getting back to the original issue the next step was to test another KNOWN SMOOTH transfer case. I drove the rig to Blaine's and we jacked up the jeep and with weight off wheels attempted to recreate the issue. Could not duplicate with weight off wheels. The rear harmonic balancer and flange were true, no wobble. The tires were definitely not balanced but that was a side issue. Blaine and his helper got to work and I did what I could to help without disrupting their system. In less than 2 hours, a different, known good 241 case was in and the rig was test drove with no vibes, no rumble, no issue whatsoever. Blaine, being the guy he is said "well its fixed, we'll look into the other case". That's the kind of guy he is. I stuck around to discuss the possibilities, and to observe the case being opened up. To the untrained eye the case appeared in perfect shape. I helped clean up and drove my jeep home with the good case, very thankful. Later,
@mrblaine emailed me that there was wear on the tone ring, about as deep as a business card, the powdered metal from the tone ring had gathered in one of the bearings and caused it to have a clunk. Blaine was under the impression this case had been "gone through" by the seller and was ready for install. The loose flange nut allowed the tone ring to be gouged by the bearing surface but still keep the pin in, over the little time I had the case installed, the wearing of the tone ring, and the debris being collected in the bearing led to the rumbles I was feeling. I am sure he can explain it better than I can. Hopefully this is helpful. I have read a few threads of people with 241 issues.