Transmission rebuild fail

[Howlite]

So i rebuilt (seals) the manual transmission and put everything back carefully using reference photos i took while disassembling, tested shifting, put it up on the car and went to drive test it, put it on reverse and then 1st gear to get out of the driveway and everything was working fine, no weird sounds or anything, then as i was on 1st gear suddenly the transmission locked up and the car came to a stop in the middle of the road, the shifter was stuck on 1st gear but it came loose carefully, tried starting it up in neutral but it would stall when letting my foot of the clutch, i tried rolling the car to the side in neutral but it wouldn't move, it only moved while pressing the clutch.

Really frustrating after putting so much time and effort into this, unfortunately ill have to remove it and disassemble it and see what happend.

Any ideas what could've happened?

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[Howlite]

Disassembled it today, nothing damaged thankfully, i guess the shift mechanism wasn't properly seated into the bell house however now, 4th gear keeps binding for some reason.

Sent from my 2201116SG using Tapatalk

[Howlite]

Fixed
Whenever i torqued down the main shaft it would bind and not turn, at first i though the 4th gear synchro was getting stuck onto the gear so i tried sanding the surface where the synchro ring meets the 4th gear, but it still would bind after putting the bellhousing and torquing the main shaft, so i tried torquing the main shaft without installing the bellhousing,
Here is a video of it.


As you can see in the video, all gears would turn but the 4th gear was locked solid, so now i was sure the problem was with the fourth gear, after looking into it closely i found out that the synchro hub was damaged where the space collar sits.



This was causing the space collar to push the fourth gear into the synchro hub which would lock the gear.



The manual states that the service limit for the space between the top of the 4th gear and the space collar is 0.3mm.



So i got a thick washer and cut the inner and outer diameter to be the same as the damaged area in the synchro hub and i kept grinding the width of the washer away until the space between the spacer collar and the 4th gear was about within the service limit (just less than 0.3mm) i couldnt go less than that because the washer would be too brittle.




The washer on the damaged synchro hub


After assembling the transmission back it worked fine.

So how did this happen in the first place?
I remember vividly while installing the bellhousing the first time i had to force it with a hammer, i believe that is why the transmission locked up while the car was moving which resulted in the damaged synchro hub.

So far It has been a month since the rebuild and i have driven the car a few times now with no problems.

[Jinnai]

Repairing a transmission sounds enjoyable when it works but a nightmare when it doesn't...

[Oldblueaccord]

Nice work man!!!

[conozo]

Sorry, i was away for a few months but I had my transmission rebuilt a long time ago and i had the exact same issue as you. Locked up completely in 1st. Then I took it all apart, found some wear on some 4th gear parts but nothing major. Put it all back together and its been fine.

The only idea i could come up with is that the shifter arms weren't seated correctly or possibly when re assembly the housing wasnt on blocks when working on it on the workbench because the mainshaft is longer than the housing. Its possible that the mainshaft was loose and sliding back and forth allowing it to be in two gears at once if thats possible.

[ShiRen]

Wonder if that's what could be wrong with mine. Grinds into 5th every time, 5th is fine though. It didn't start doing it immediately after I had it open though

[conozo]

Wonder if that's what could be wrong with mine. Grinds into 5th every time, 5th is fine though. It didn't start doing it immediately after I had it open though

Around 50,000 miels later I did have a separate issue with mine which was the mainshaft nut came loose on its own which caused the 5th gear to grind and wine. Tightening it up would have fixed it but it was missing a tooth by the time took the cover off to inspect it. I did drive it like 10,000 miles with that mainshaft nut completely backed off. Kind of amazing it worked at all if you think about it.

[ShiRen]

I mean I inspected it and couldn't find anything wrong...