My shifter locks in first sometimes on my 49 fleetline. To unlock it I have to open the hood and move the two shift rods. I tried a shim by the the 2nd and 3rd arm inside, did not work Any info on this fix on some one who had this problem. LEN
You can file down the cover so the levers are not so sloppy. Also there was an aftermarket kit sold years ago with an interlock that prevented it from going into two gears at one time.
I had this thing years ago. if you can find one of the kits WESTERN AUTO sold years ago it will help.. but the main thing to prevent this hang up is have the clutch fully pressed all the way down before moving the gear shift. just slow down shifting out of low gear in till the clutch is pressed all the way down..
sorry i don't recall the kit name .don't think they are available any more.checked FILLING STATION catalog didn't see it.
if don't move the shift lever in till clutch is fully pressed down. most likely you never have any trouble.
a rebuild of selector box is only fix. look at this.https://www.google.com/search?q=1954+chevrolet+gear+shifter+box&tbm=isch&imgil=_uBUY9AJFMZvTM%253A%253BJeVMLIXFF6b6qM%253Bhttp%25253A%25252F%25252Fvcca.org%25252Fforum%25252Fubbthreads
there you have to weld up worn surface and file them like they where new. just slow down ,and have that clutch down then move the lever. best of luck to you..