Transmission shifter rolls

[cjl7516c]

I have a 77 spider with a 5 speed that has been rebuilt a couple of years ago. I have a problem shifting into 5th sometimes because the shifter misses and the handle rolls in my hand. I can recover by pulling down into 4th and then trying again, and then it will go in. It's a bit disconcerting when getting on a freeway and having to mess with that sometimes so any suggestions?

[So Cal Mark]

the pivot parts on the bottom of the shifter could be loose or worn. Or, the tranny could have the wrong shift rail/shifter combination

[cjl7516c]

I put in all new parts on the shift lever right after the transmission was redone. I had trouble with the lower nut coming loose so I finally ended up putting on a nylock nut, which seems to have fixed that problem. The other thing you mentioned I have no idea about, but wouldn't the person who rebuilt the tranny have noticed that?

[So Cal Mark]

if you have a problem with the lower nut loosening constantly, the lower cup may be worn. If the hole is enlarged, the nut won't stay tight.
As for the rail/shifter mismatch, we see lots of them so I doubt it gets noticed often