Hi Johnny, I never tried moving it in or out. It is at the shop with the car so I cannot try it. Maybe the next time I go down I will see how much movement there is. It isn't just for harmonics as the ram truck has a full floating rear axle like our cars and they have quite a bit of travel in the suspensions.
I would assume it has quite a bit of slip, but I would be very curious to know! I was surprised to find out the cars really don't have any, but they have that whole IRS cradle which as you are alluding to, doesn't move much if any.
