The easiest way that I've found,is that a t 19 wide will have a groove machined all the way around the splines on the input shaft about an inch back,and the t 19 close will not.I do not know if this holds true to all t 19's,but I have 5 of them,2 wide married,1 wide divorced,1 close divorced,and 1 close married,and it holds true on all of them.