Gearbox Issues

[biltong_nz]

Looks like the cold night got the better of her.

Warming the car up this morning when all of a sudden she decided to lurch forward and stall without me doing anything. Started up again in neutral and with foot on the clutch, took foot off the clutch but still wanted to go forward and stall even though it was in neutral. Seems like it's become lodged in a higher gear, and when another gear is selected, the car doesn't want to move instead just stall when the clutch is released. Does anyone have any advice?

Cheers,
Billy

[oldschool]

It sounds like one of the selector fork pins has broken in the shaft after it's engaged a gear.
There's 3 selector shafts with forks..reverse, 1~2 and 3~4 The gear lever will feel to operate as normal with a broken pin..just the shaft is moving not that selector fork!
If it's stuck in 3rd or 4th and then you put it in 1st or 2nd...the gearbox will be in 2 gears at once, which locks it up...hence stalling when you try to move.
The gearbox will need to come out and the top cover removed to get at the selector shafts and forks to replace the broken pin...probably a good idea to replace all the pins and also flush out the gearbox to remove any broken pin pieces. Refill with 20/40 SF oil when refitting...cheap at The Warehouse.

[TheMechanicnz]

I've got a gearbox here for parts. Just tell me what you need and I'll see if ive got it.

[biltong_nz]

UPDATE:

So I towed it to the mechanics on the Monday, 4th July, in the hope they would get it done by the time I got back from Wellington on the Thursday. But it hadn't even been looked at so I got it towed back and decided I'd just get the box out myself. But, after taking the top cover off, I see nothing of concern.. Maybe just low gearbox oil? Also Spigot Bearing? looks very worn with a bit of rust, but would that cause the symptoms I had?

Link below has a pic of top cover removed and spigot bearing

https://www.dropbox.com/sh/v41f8xrvpgokixc/AADW-k5767j8QQ3hY1rjjDE7a?dl=0

[biltong_nz]

Another update:

Runs through all the gears but refuses to select 3rd. In neutral you can spin the input shaft of the transmission and the output shaft spins, but when you select a gear neither spin. Just making sure that is correct?

[TheMechanicnz]

I could be wrong, but it sounds like it is stuck in 3rd gear. In neutral the ouput shaft should remain stationary when the input shaft is turned. And the opposite in gear. If the box was stuck in 3rd while in neutral it would allow the output shaft to spin, then when you select another gear you are essentially selecting 2 gears at the same time locking the box together which would cause the issues you are describing.

[oldschool]

From the photo it looks like it's stuck in 4th gear. Check the selector forks are moving all the way in and out of the gears selected when you move the gear lever. I suspect the 3rd~4th selector fork has a broken pin, hence the reason it won't go into 3rd gear.

[biltong_nz]

Finally fixed!

Box has been at the mechanics for nearly two weeks as they have been working on it in their down-time to save me money. Turns out something in the gearbox had ground itself down so it was stuck in 3rd. So they had to re-machine to how it was or something like that. Oh, and even working in their down-time, still costing me $800! Oh well, next step is to put the box back in and then I'll be happy