I have the sky crossmember as well but I'm not running any drivetrain lift so nothing is contacting the body. I did have to notch the horse collar to get the drive shaft to clear but there is a ton of space there now so no contact. The 84/85 shaft is very common for this application and I would think there would be a lot of info out there if it caused this issue.
I originally had an 8 degree shim in there, and went to a 10 to try to correct this. it maybe made it better but not a huge improvement. In any case the pinion angle is where it needs to be now, so that isn't the culprit.
I think the fact that it is only happening while on throttle and is not RPM dependent is telling me it's related to that driveshaft somehow.
I'll pull the shaft and get it up to speed in front wheel drive and see if I notice anything (other than my truck wanting to rattle apart from front vibes, haha)
It seems unlikely that the driveshaft place would have missed an issue with the CV end of the shaft, but anything is possible I guess. At this point I should have just bought a tom woods
