Sounds like your caster is way off have you gotten an alignment latley, x2 on what silver said 886 springs are 650# rated compared to stock is like 550# plus they give 3 in of lift
Its probably the drive shaft angle causing the noise try a diff drop, some have success with this. If the diff fluid is an off color its contaminated, angle on the drive shaft should not effect fluid color
This is avery common problem on all lifted tacos across the board and the fix is indeed a one piece drive shaft or some see results from washers in the carrier bearing