Here's my experience with my '90 Blazer w/ a 700r4, NP241, and a Dodge Dana 60 front end:
I put a 4" spring lift on my truck and added a 1" EZ-inch from DIY4x to relocate my axles. My front axle was pushed forward 1.5", theoretically improving the front driveline angle. I had problems with the front driveline rubbing on my trans crossmember. Took me a while to find it, as I assumed it was in the CV.
Things I did in the process of finding that I needed to clearance my trans. crossmember:
1. clearanced the cv on the shaft.
2. tightened up the transmission mount bolts, as they were slightly loose.
3. checked that the trans. mounts were still good.
4. Finally realized, with the help of CK5, that with the bit of axle wrap you get on the front axle under load, combined with going uphill causing the suspension to unload, that the shaft was hitting the crossmember. I cut a small chunk out, and I've never had another issue with it.
Folks told me it couldn't be my crossmember, but it was.

Look for scratches on it.