If you're not using a double cardon shaft, the pinion and the t-case angles should match.
http://www.4xshaft.com/images/2joint_angle.gif
I had this issue on my truck but it was in the front with a 3" lift. I installed a double cardon shaft and all was well. There were no vibes, but I had an awful roar, or rumble, when off the gas, and it got really bad when coasting down a hill at speed (like on the Interstate).
If you did a Toyota swap you have a drive-shaft with 1310 u-joints. What kid of shaft do you have? GBR? What size lift you running? What rear trailing arms? Do you know your pinion angle? Is it greater than 3*?
http://www.4xshaft.com/images/2joint_angle.gif
I had this issue on my truck but it was in the front with a 3" lift. I installed a double cardon shaft and all was well. There were no vibes, but I had an awful roar, or rumble, when off the gas, and it got really bad when coasting down a hill at speed (like on the Interstate).
If you did a Toyota swap you have a drive-shaft with 1310 u-joints. What kid of shaft do you have? GBR? What size lift you running? What rear trailing arms? Do you know your pinion angle? Is it greater than 3*?