[DanEC]

Besides the rubber boot, a longer shot possibility is that the shifter is centered in the chrome ring over too far to the right and interference between the ring and shift lever is preventing it from going all the way into gear. Kind of unlikely that it would be blocking both 3rd and 4th throws however. The height of my transmission tunnel above the toploader transmission makes the shifter pattern pretty tight within the chrome ring. I had to do some careful fitting to avoid interference.