Fixing a broken 5MT- a journey

[Pearldrummer7]

Hi all,

Let me preface this by saying I've never done actual transmission work before this.


I have a 5MT with JDM RA gears, and it wouldn't consistently shift into gear (mainly 1 and 2, but sometimes R as well) when in the donor car. I was told by the seller that it was just a fork, and could be replaced easily. I opened up the transmission and found something a little different than that.

This little plastic guy was broken off and stuck in the input shaft. The shaft clearly grinded away part of the this plastic oil-return piece, and grinded into the metal as well.

https://farm3.staticflickr.com/2911/14034266628_886d26ca23_h.jpg (https://flic.kr/p/noahwh)
https://farm3.staticflickr.com/2909/14218483762_3bbd12c45a_c.jpg (https://flic.kr/p/nErrRL)


The bolt on the end of this shaft wasn't even hand tight. 5 and R were so loose you could move them around with just a finger. Also, that bolt is HUGE. My 32mm is too tiny, so I haven't tried torquing it down and seeing how things mesh.


I think I am buying a used LGT transmission and putting the gears into this case, as I know this transmission has just a bent fork, and I believe LGT gears are a lot stronger than the 2002 WRX ones.




Does anyone have any input on any of this?

[Ironhydroxide]

one warning, the LGT synchros need a different 3/4 shift fork, as the dimensions are slightly different for shift slider location.

second warning... you NEED to make sure the engage depth of the Pinion is correct, which takes a special tool you can get from Subarugears or Subaru themselves.

third warning.... Good luck, PM me if you need some advice.


Edit:
that said, this is likely fixable. i bet what happened is the nut wasn't torqued to spec properly, or the tangs weren't punched in correctly. The nut spun off, and then the bearing just behind worked itself loose allowing the input shaft to slide backwards into the casing breaking the plastic oil feed.

the 1/2/r shift issue sounds like a bent fork, which is not EXTREMELY horrible to replace... but it's tedious to get everything correct again afterwards.

[Pearldrummer7]

one warning, the LGT synchros need a different 3/4 shift fork, as the dimensions are slightly different for shift slider location.

second warning... you NEED to make sure the engage depth of the Pinion is correct, which takes a special tool you can get from Subarugears or Subaru themselves.

third warning.... Good luck, PM me if you need some advice.


Edit:
that said, this is likely fixable. i bet what happened is the nut wasn't torqued to spec properly, or the tangs weren't punched in correctly. The nut spun off, and then the bearing just behind worked itself loose allowing the input shaft to slide backwards into the casing breaking the plastic oil feed.

the 1/2/r shift issue sounds like a bent fork, which is not EXTREMELY horrible to replace... but it's tedious to get everything correct again afterwards.


Iron....

Which "pinion" are we talking about, exactly? Exiting the case?
Edit: Am I changing pinion depth? I thought that was only for the driven (output) shaft? I will be only modifying the main (input) shaft, I believe.



I took apart the input shaft to find that one of these clips is missing entirely (and one wasn't installed, but they were easy enough to pop in):
https://farm3.staticflickr.com/2896/14042282900_e17260e2ee_h.jpg (https://flic.kr/p/noSntS)

https://farm3.staticflickr.com/2929/14042240668_6da055ad3d_h.jpg (https://flic.kr/p/noS9VJ)

I installed it and reinserted the shaft into the case.

It's very clear to me that this nut wasn't tightened with a socket, but with a crescent wrench or something. It has big marks in it on 2 of the 6 faces only, in the tightening direction. I think this is the root cause of this issue. Also, when the shaft was slid backwards a little, it wouldn't engage the gears. You had to push it back to the correct spot for them to engage. Might all be the same issue, I'm thinking!






Thanks for the advice. Your thread on transmissions is AWESOME!