I'll have to look, but I think there's a bushing in the bottom end of the shaft through the firewall..... it's usually kept tight by the spring between the rag joint and firewall bushing... . other wise, I'd think it might be some loose wireing running up the steering column bouncing or perhaps a wire connector in that area up to the firewall..... then there should be a bearing/bushing under the steering wheel, and if you have tilt steer, a u-joint of some type under that..... I know in my '84, the whole column itself had worked loose, and would slightly move up and down, forward and back. Not much to do for it but some rubber splicing tape around the column where it clamps to the dash.....