Brindling means that the needles have caused the cross of the unjoint to have rough spots on them, I have the same symptoms in my freight liners, they are great underpower but when they run on compression of the engine they howl,sound rough and you can feel them through the floorboards,
Some times you can't even see it but you can feel them on the cross of the joint
Sorry about the late post,
I figured you meant some sort of binding. I think I need to go thru the whole shaft this winter while the truck is stored.