unreasonable displacement values - driven from torque load

Hi, I'm hoping someone can assist, I am getting extreme displacement results whilst my surrounding structures all comply within a safety factor of 3 of the yield limit of material. I have narrowed down the issue I believe to a torque load on a shaft, I have noticed I can only apply the torque load span to 180 degrees of the shaft, this gives me an unbalanced load I believe, I have tried reducing this by 50%, but this still remains unbalanced....... I cannot apply a second torque load to the same shaft surface for the remaining 180 degree span. I was wondering if anyone has come across this issue before? my alternative thoughts are to model an additional shaft to apply the remaining torque and span, but this doesn't feel like a correct process, any additional thoughts would be greatly appreciated, thank you all.