does anyone know what this transmission spring does on a 48 DeSoto?

[marcapra]

First of all, I can't find the gearshift selector crossover spring that goes on the gearshift crossover plate.  The Parts Book describes the spring as being 5/8 O.D., 3 1/2" long, with 24 coils.  Is this spring supposed to be stiff or weak?  It's hard to find a spring that fits because the left side of the spring has to have about 1/4" gap to fit around an iron flange.  I had to pull one side of this spring to make it fit, but it made the spring weak.  And out of curiosity, does anyone know what this spring does?