Posted in the general forum but getting no responses. It's a 2006 SUT, but the driveline is the same in both. I used the Tremec tool box app on a I-phone to give me the angles, you need to put 3-4 layers of electric tape on the side of the phone to keep from pressing the power button and scratching the phone. I got a angle of 3.9 deg. On the transfer case/shaft and 3.6 degrees on the front differential but angled the wrong direction, which seems opposite to conventional wisdom and creat vibration from what I've read. I'm fighting a huge issue with harmonic vibration and wrecking transfer case bearings and u-joints. I've replaced u-joints, balanced shafts, on my third rebuilt t-case from Transfer case Express, and now this one looks like it may now be junk at about 400 miles. The vibration come on at around 63 and worsen slightly with increasing speeds, increased vibes when acceleration under loads or going up hills. We just arrived for the 4th after driving 190 miles and I noticed it the driveline started howling at around 65-70 like a pinion bearing or something. Upon arrival the transfer case was so hot you could not touch it more that 1/2 a second and seeping oil from the front and rear shaft seals...Also tried 4 hi lock briefly and it made some groaning scraping noises when turning and it was binding up. Didn't want to move without hitting the gas. I have gone through everything, driveshafts are checked for runout and indexed for the smoothest operation. I have put new solid bushings in the front differential just before the trip. Made no difference in vibration. If you pull the front shaft and run it in 4 hi lock, vibes are completely gone. I have checked the front driveshaft angles and see a big problem that can't be fixed so chime in if your trucks are the same. So to review my main question...The front driveshaft u-joints are in the wrong plane, opposing each other. The front transfer case angles upward, the front diff angles upward also. The front diff should parallel the transfer case pointing down correct??? This looks like the cause?

For anyone wiling to check their angles, you have to put the t-case in neutral and lift the front end so you can rotate the shaft and remove the bolts at the front differential to measure off the face of the u-joint retainer strap surface on the yoke. Needs to be turned and level before measuring. Then re-install and measure off the driveshaft. Same at the t-case but you can leave shaft installed and measure t-case angle along the driver side edge of it but watch that you get it flush and level when measure, there is some molded numbers on the case that get in the way when measuring, the measure the shaft angle again to get the final readouts.

I actually measured the t-case side first then differential side, so readings correspond with mine when measured.

Ok, measurements have changed since solid differential bushings were installed and they are worse. Here are the pics of how to measure.
Transfer case measurement on output shaft, not that the phone needs to be close to square or straight up/down and mimic the driveshaft pointing straight ahead or perpendicular to the t-case.
Phone on driveshaft measurement is next. Keep phone inline with the shaft.
Front differential measurement is last, measurement taken off face of the yoke, yoke needs to be level first. Note that the angle indicates its pointed up, it should be down I believe.... Usually have to have the front wheels off the ground to do this or roll the truck ahead or back to get it level. I measured the yoke across the short way last time and angles were as noted in the first post. They are much different now... May need to measure both ways.
Today’s final measurement the app spits out is way out of spec. Angle 1 is transfer case u-joint, angle 2 is front differential u-joint. Gm calls for a max of 4 degrees of driveshaft u-joint angles.