Technical Nanni 5 speed gear selection problem

[cinque500]

I’m having awful gear selection problems with my box. It started after I changed first gear as it had become damaged. I then had trouble selecting fifth gear whereby it wouldn’t engage and attempting to select 5th meant it then also wouldn’t go into third or fourth. I had to slow right down and go to 2nd, after which third and fourth could be selected as normal and I could go up and down 1-4 no problem. Re-attempting to go into fifth caused the issue again. Now the lollipop was very blown on one side and the rubber soft and squidgy so I fitted a new modified one cut down as appropriate for the longer transmission. Then hey presto, I had a perfect gear change, all five gears and reverse, up and down the box, snicketty-snick into gear beautifully. Did a few miles on it, no more than that, all good and put the car away. Then went to use it again yesterday and it’s back to the old issues again, yet nothing has been changed or touched. I’ve tried adjusting the gear selector box position but no joy, in the garage I either cannot get reverse at all or I get reverse in 4th and R positions. It’s driving me up the wall - I do not know what else to do!

 

[the hobbler]

I’m having awful gear selection problems with my box. It started after I changed first gear as it had become damaged. I then had trouble selecting fifth gear whereby it wouldn’t engage and attempting to select 5th meant it then also wouldn’t go into third or fourth. I had to slow right down and go to 2nd, after which third and fourth could be selected as normal and I could go up and down 1-4 no problem. Re-attempting to go into fifth caused the issue again. Now the lollipop was very blown on one side and the rubber soft and squidgy so I fitted a new modified one cut down as appropriate for the longer transmission. Then hey presto, I had a perfect gear change, all five gears and reverse, up and down the box, snicketty-snick into gear beautifully. Did a few miles on it, no more than that, all good and put the car away. Then went to use it again yesterday and it’s back to the old issues again, yet nothing has been changed or touched. I’ve tried adjusting the gear selector box position but no joy, in the garage I either cannot get reverse at all or I get reverse in 4th and R positions. It’s driving me up the wall - I do not know what else to do!

Sadly, it would seem that the only answer is to heave the box out and have a good look at it. One thing I was told about these 5-speed conversions is that they are ONLY a 'cruising' gear and NOT an 'accelerating'gear. This is because the shaft for the 5th gear is only supported at one end.

 

[cinque500]

As you can imagine I’d rather not! I’m puzzlingly over it not working with the old lollipop, working perfect upon fitting the new one and then reverting back to playing up?

 

[Bounding Bambino]

I would take a wild guess, and maybe suggest that the "new" lollipop might have failed, or began to de-laminate. Even new parts have questionable quality nowadays. Wouldn't hurt to make sure everything is correct underneath after being parked for some time?.

The only other thing that could be causing issues, if there isnt any mechanical damage on the gears. Could be issues with the selector "interlock" plungers acting up. IIRC, the 5 speed kits retain the factory selector plungers small spring loaded mechanisms that prevents 2 gears from being selected at a time. And ride on indents on the gear shift fork shafts. Maybe by chance that system is binding and causing this erratic behavior. Unfortunately they are only accessible from the top of the transmission. The small side access plate only retains the "indent springs".
Then again those springs/balls might be weak and allowing multiple forks to move between shifts and causing the shift fork interlocks to catch and bind.

A strong indent is important to hold the gear train in neutral, when you do a shift. So as your shifting, the 2nd gear fork doesn't try and engage at the same time.

The parts manual shows the complete components over a few pages. Unfortunetly not all on one page.

 

[cinque500]

I’ll get the lollipop out and check it over. It’s only been on a couple of months but as you say who knows with pattern parts. I’m happy with the indent springs/balls doing their job ok. But I’m sure there were no springs present on the interlock plungers, which is a worry! Have you got the page for that part of the ‘box?

 

[Bounding Bambino]

Apoloigies for the confusion. There are no springs on the interlock plungers. however there is a specific order they go in. This is all i could pull up out of the parts manual.

 

[cinque500]

Apoloigies for the confusion. There are no springs on the interlock plungers. however there is a specific order they go in. This is all i could pull up out of the parts manual.

No probs, appreciate your ideas. On the plungers iirc I’m ok as they can only go in one way as there are two thin ones and a fat one in the middle