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Discussion Starter · #1 · (Edited)
Recently I've noticed that the shifter on my '04 STi has become a lot harder to shift, expecially at higher rpm's. Is there any sure way to tell whats wrong with the tranny? I have only launch the car occassionally, and never at more than 5k revs, and have since stopped launching all together after the harder shifting problem came. It seems to take a lot more force to shift the tranny into any gear while the clutch is pushed in while I'm cruising on the freeway, any guesses as to what might be wrong? Synchros?

Thanks!

edit: after reading some more about tranny's, could it just be the tranny fluid?
 

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when a synchro dies you'll get grinding going into gear. Even if you shift super smooth and slow.

now that the USDM sti has been on the market a while folks are starting to see 4th gear synchro die (myself included). This is because there is too big a jump in ratio from 4 to 5 to 5 to 4 downshifts really overwork the synchro. The JDM trannies have closer ratios. You can blame subaru making compromises for MPG for this one.
 

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^^Is this on 04 - 05 MY only?
 

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Turninconcepts.com said:
when a synchro dies you'll get grinding going into gear. Even if you shift super smooth and slow.

now that the USDM sti has been on the market a while folks are starting to see 4th gear synchro die (myself included). This is because there is too big a jump in ratio from 4 to 5 to 5 to 4 downshifts really overwork the synchro. The JDM trannies have closer ratios. You can blame subaru making compromises for MPG for this one.
Just great. Looks like I get to start rev matching between 4th and 5th. Never thought I'd be doing that between those two gears.
 

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^^ you would have to start double-clutch rev matching. rev matching alone won't save wear and tear on the synchros.
 

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^^ :lol: mpg would probably be pretty bad on the hwy.
 

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boondocksaint said:
^^Is this on 04 - 05 MY only?
Don't know. I'd have to look at the ratios for the 06 and how they compare to the 04 and 05.

For that big of a jump in ratio you should be double clutching the downshift from 5 to 4. Unfortunately, I did not start doing this soon enough, and my 4th synchro is dying. Bad Clint.

Now, what's my options? Well, I've got a few ideas I'm working on so we'll see how it plays out.
 

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Discussion Starter · #11 ·
thanks for all the info, i guess its not the synchros since I haven't had any grinding at all.

Any idea on what the hard to shift problem might be? I have to push the shifter prety hard to change gears when the clutch is all the way in while im cruising on the freeway.
 

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have you had anything done to the shifter, such as a short shift kit or is it oem? if you have, check the bolt for the pivot bushings to make sure it's not too tight.
 

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pooster.online said:
thanks for all the info, i guess its not the synchros since I haven't had any grinding at all.

Any idea on what the hard to shift problem might be? I have to push the shifter prety hard to change gears when the clutch is all the way in while im cruising on the freeway.
It could be any number of things -

- Clutch not fully disengaging
- Problem with the linkage
- Problem with the pivot
- Bent shifter fork


as was said - tell us if you have any mods or have made any changes to the clutch or linkage or tranny.
 

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non-ricer said:
Care to fill us in on those ideas Clint?? hehe...
I've got a good spare 04 6mt on the way to swap in while I work out all the details.

First, and foremost no matter what I do I'll be upgrading the front LSD. Probably with a quaife unit as we have a distrib account with them.

My first idea is to got with the 1-4 PPG straightcut gearset with dog engagement and keep stock 5 and 6. Even with vendor cost that setup is big $$$ (HUGE $$$). I'm not sure I can swing that much, and since TiC is small and we use our cash to purchase inventory I'll be paying out of pocket.

I've got another idea of to just go with stock gearset, steel shifter forks (why not), and JDM 5 and 6.

I've also got another idea to go with stock 1-4, jdm 5 and 6, and see if it's possible to do dog engagement on at least 1 and 2.

I've also got a nutty idea to step up to a 4.44 (would really like a 4.11) final drive.

Right now all of this is up in the air, and will probably take quite a bit of time to come to light. That's why it's a good thing I've got a good spare trans on the way.
 

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Turninconcepts.com said:
My first idea is to got with the 1-4 PPG straightcut gearset with dog engagement and keep stock 5 and 6
PPG. I was talking with a friend who works at an install shop in MD that works with PPG. He was telling me aside from the baddest sounding transmission, the 4th and 5th ratios are the same, so in essence, you just end up shifting 4th straight to 6th, effectively making a 5 spd.

Then again, you probably know all that, if this entire board doesn't already.

He has the straight cut PPG gears in his WRX 5spd and it sounds gnarly, almost like its in reverse (my first experience with a straight cut box, and I call myself a car guy).
 

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Discussion Starter · #17 ·
It could be any number of things -

- Clutch not fully disengaging
- Problem with the linkage
- Problem with the pivot
- Bent shifter fork


as was said - tell us if you have any mods or have made any changes to the clutch or linkage or tranny.
Everything regarding the drivetrain is completely stock. There's no real problems with the tranny except for the fact that it takes a lot of force to shift gears while im at freeway speeds.
 

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Turninconcepts.com said:
My first idea is to got with the 1-4 PPG straightcut gearset with dog engagement and keep stock 5 and 6. Even with vendor cost that setup is big $$$ (HUGE $$$). I'm not sure I can swing that much, and since TiC is small and we use our cash to purchase inventory I'll be paying out of pocket.

I've got another idea of to just go with stock gearset, steel shifter forks (why not), and JDM 5 and 6.

I've also got another idea to go with stock 1-4, jdm 5 and 6, and see if it's possible to do dog engagement on at least 1 and 2.
here's another idea: 1-4 ppg straightcut/dog with jdm 5th and 6th.
(phil gets credit for that one)
 
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