Probably not gonna be much help. But here it goes.
Get under the truck and spin the d-line by hand and see what/ where it is binding. If the yoke is hitting the yoke, the angle is too extreme. (too much lift)
81 toy's have the short tranny, leading to a crappy u-joint/pinion angles for the front when lifted.
Possible solutions.
New driveline w/ newer yokes. Newer yokes (84+) have a greater angle before binding. (Call Jesse @ Highangle drive line)
Drop (lower) the t-case x-member with spacers. If done enough, might be able to relax the angle @ the yoke. (although i have not seen anyone do this w/ a toy)
Swap in an 84+ manual tranny. These are 4 or 6 inchs longer than the 79-83 trannies and will help your u-joint angles.
And my favorite.. Put in double t-case. That's fix any/all binding d-line issues.
