Your driveshaft angle of 22 deg is kinda steep. Judging by the pics your rear pinion angle is alot higher then 8 deg. its hard to get a good reading on it. Easiest way is to disconnect the drive shaft and read flat across the yoke. Your rear seems to be ok but if you look at the t-case yoke your angle is way to steep. As it spins it will start to wobble (vibrate). You need to reduce the angle. I would try a 1in drop. any more then that and you will start to have other isues. (shifter, cables etc). pull one of the 6 bolts on the t-case and go buy 6 1in longer (grade 8) and a bunch of 1/2in washers. i would start at 1/2 of drop and keep adding washers till it goes away. this should make a huge difference. this should also reduce your driveshaft angle. As long as the bolts come out easy it only takes about 10min. Do one side at a time and make sure to get a jack under the t-case shield. I just went through this exact same issue but i was too steep on the pinion and did crazy amounts of research. good luck !!
P.S. everyone is right. you will be looking at a SYE in the future.........
I would lengthen that driveshaft before ordering a drop. Longer shaft means reduced angle. It should be riding on the slip yoke where it rode before you lifted it. Put your money into keeping it lifted. Dont lift the suspension just to lower the center. Do it right.
when you drop the TC it will move the yoke into the TC more!!
leave the shims for now. dont order a t-case drop. you can use longer bolts and washer to drop it. this way you can see what you need. you can either leave it like that until you get an sye or order the plates the correct size after you judge it with the bolts and washers. it works perfect and its what most guys do.
TC drop, until you can get the SYE/CV set up. Odd's are you'll end up lowering the TC the same amount as you lifted it....or real close, which will put the drive shaft back in it's stock position this is not the best case scenario but it'll work until you can get the SYE/CV set up. I used the SYE/CV set up, along with some 8* shims when I left my YJ 4 inches. Oddly enough I didn't get any vibes prior to the SYE/CV set up, but my drive shaft did look like it was ready to drop out of the SY...like yours.
Moab Trails I've done: Onion Creek, Long Canyon, Dome Plateau, Top of The World (2), Fins-N-Things (2), Poison Spider,
Golden Spike, Gold Bar Rim, Hell's Revenge (2), Baby Lion Back, Cliff Hanger, Moab Rim, Kane Creek Canyon, Strike Ravine
If you get bolts that are 1-2" longer, you can just replace your current bolts with them to measure how much drop to get it where you want. You wouldn't drive this way because there would be a big gap, but you can measure that gap to figure out how much you need and how much angle change you see in 3/4" vs 1" vs 1.25" etc.
You will probably have to do a TC drop until SYE time.
You COULD remove the shims which would be better in the sense you're not losing ground clearance in the center, BUT you run into the likelyhood of binding the joints.
Ok, 4 of the 6 tc skid bolts let loose. Hoping the other two do with the compressor. Its filling as I write this. Ill be running to homedepot for the bolts. Ill post back with more angle pics when I get them.
Black 1993 YJ 4.0, 5 Speed
Slowly but surely getting better and better. Trailer build soon!!