constraining to local axis doesn't work when animating.

[bvmadjen]

I'm using Softimage 2015 SP2-R2.
I was attempting to animate a piston (piston, piston rod, and crankshaft) to simulate a two stroke engine.
It only works if I use a global constraint for the piston. if I attempt to do a local constraint, it doesn't work at all, which makes constraining virtually useless (since Softimage, by default, uses global transformations for animation).
I've used expressions to only allow movement on a specified axis (z), and it doesn't work at all.

[opoppopopp]

post that error scene, or video, or screenshots, otherwise people won't be able to identify the error.