Medium duty transmission - possible to refresh pattern?

Hello all,

I've got a couple of medium dutys. One is a dump with a 10 speed Spicer (high low selector on the shifter) and the other is 5 speed Spicer with a split rear end. The shifters in both trucks seem to have excessive play side to side and the pattern is somewhat sloppy (meaning the location of the gears is kind of vague). Is it possible to replace springs or what have you to have the shifter be more precise? It would be nice to feel the H pattern or the different paths for each gear be a little tighter. Also, I realize the shifters in these medium dutys are heavy but it would be good for the shifter to want to return to neutral. I've never driven a new (or rebuilt) transmission of this type but I imagine when the trucks were new, the shift pattern was a little tighter.

I hope this will make sense to folks. Any help is appreciated. Thanks

A.