Dumb question about transmission/gearbox operation 680e

Guys this thing I bought has had quite a few thing isolated and removed to keep it going by the previous (cane farmer) owner and most of the fencing wire has been removed.
After repairing the shuttle transmission it seems to work fine in both fwd and rev but changing gears is a problem.
I don't understand is how the gear change works. At the moment to change gears I need to put the forward reverse lever into neutral, change to 2nd etc then put the transmission back into forward again. If I don't the 4 speed box won't let me change and crunches.
Is there a valve or something that has been removed that puts the transmission into neutral or pressure off the clutch to change gears or does it rely on the synchromesh system and mine are worn out. I read the operators manual and that doesn't give any real information just reads "Shifting - The synchromesh four speed transmission may be shifted to high or lower gear without stopping the machine".
I'm not much of a tractor operator other than a Massey 40B I still have but it has a clutch so this is all new to me.

Derek

What you are describing sounds exactly normal.
You must shift the shuttle (FNR) to neutral to shift the 4 speed - even on the go - without the need to stop the tractor.
When you drive a manual car or truck, pressing the clutch pedal - engages neutral
You just can't - shouldn't- change direction "on the go" - you should be stopped or almost stopped to do so.

From memory, I don't think the 680 gives you a declutch option unless you apply the brake - I might be corrected on that.....

I can't speak specifically to the E series, but I owned a couple of Gs, and there was a button on the floor that you were to step on which would put the shuttle in neutral, just like using a clutch.

I was roading it one time, and when I took my foot off the button, it failed to re-engage. I was shifting from first to second gear, and right smack in the middle of an intersection. Popped the brakes on, rolled underneath and figured out what was stuck (been too long for me to be able to describe now what it was), and got on my way.

I never trusted it again, and just did as alrman describes, shifting from F to N before changing gears in the 4 speed box. It didn't take a whole lot of practice to get proficient at it.

That's a load off, I was concerned something else was broken or worn out and more money to be spent.

Much appreciated

Derek

The 4 speed gear box is a synchromesh transmission. You should be able to shift it between all four gears when the shuttle in neutral. Doesn't matter if the tractor is rolling or at a standstill.
You have to let the synchronizers have enough time to spin the gears so that it can be shifted with ease.
Especially when downshifting from 2nd to 1st while the tractor is moving.
Put the gearshift lever into position for the selected gear and and gently put pressure against the it (the gear). That is what causes the synchronizer to start spinning the gears so that they can engage.
A broken synchronizer(s) will prevent any shifting unless the tractor is at a complete stop and the shuttle is in neutral.
I have attached the parts diagram of the gear box so you can see the synchronizers.