Case 580 ck shuttle id rockford or twin disc

I thought a while back i had read on here somewhere a post by Phil on how tell the difference between the rockford shuttle and the twin disc shuttle.I have looked hi and low for this post but no luck yet.I am trying to figure out which one i have does anyone know how to positively id rockford vs the twin disc any help would be great.

Case 580 ck shuttle id rockford or twin disc