Gearbox Replacement

[Nachoooo]

Hi all. In our 1999 BH Legacy TS-R Wagon, 3rd gear has been notchy for a while now, some have said the syncro\'s are worn out? Guessing if this is true, a gearbox swap is the only realistically cheap option? Sure, only 3rd gear is a small issue, but it\'s one of those niggly things I don\'t like haha.

If that\'s not necessary, and there is another solution, would anyone know? Also, the oil hasn\'t been changed in a while, in fact can\'t remember the last time it was, though with the problem only being in 3rd, is it oil related?

If it comes down to a swap, I\'ve seen a few options around. Now, our engine is a stock EJ20 n/a. I\'ve seen the gearboxes off a turbo are a longer ratio and at 100km/h sit at around 2600rpm, yet our stock \'box sits at around 2900 rpm @ 100km/h. Is it stupid of me to even think about swapping in a longer ratio \'box in replacement of the stock \'box?

[kamineko]

its not stupid, but i wonder if lack of torque will be an issue at 2600rpm/100kmh? someone around will have tried it

yours is the DOHC 2L eh. should be ok?

something to bare in mind (other than the rear diff to match) is that the clutch is hydrolic pull-type on the turbo boxes. you would need to swap in the turbo clutch system to make it work

[Nachoooo]

Yeah, that was what I was wondering about... But I don\'t mind it cruising like that on the flats and changing down for a hill... But yeah, just whether it\'s too big of a change.

Ahh right. So the turbo clutches will be different from (what seems to be) a standard hydraulic clutch? What is the difference between the two?

Thanks

[kamineko]

i was under the impression the NA clutches are cable driven. hmmmm are the BE/BH models all hydrolic push? i might go look that up

[Nachoooo]

Hmmm, well there\'s definitely a clutch reservoir in the engine bay... And lines that look to go to where the clutch belongs? Could be a TS-R feature maybe? Found they\'ve got Impreza sized rotors instead of the big or small legacy rotors hahaha... Weird things

[kamineko]

hokay so forget the cable thing you should have a hydraulic push type clutch

the turbos use a pull type clutch. a turbo gearbox will require a turbo clutch / slave / fork. easy.

[Marky]

Not sure where this 2600rpm thing has come from?

My understanding is most/all GTB/B4\'s come with the TY754VBAAA box - ratios are here - http://www.catherineandken.co.uk/sti/trans.html - and mine sits from memory about 2900 in 5th @ 100kph - stock size/profile tyres

Maybe if combined with 4.1 or 3.9 diffs you could have moonshot gearing?

[B4 2000]

 Marky said:

Not sure where this 2600rpm thing has come from?

My understanding is most/all GTB/B4\'s come with the TY754VBAAA box - ratios are here - http://www.catherineandken.co.uk/sti/trans.html - and mine sits from memory about 2900 in 5th @ 100kph - stock size/profile tyres

Mine did 2600 RPM @ 100km/h in fifth (Rev C and D have longer ratio than A and B) also 4.444

Now i have 6speed and it sits bout 2900 RPM in sixth @ 100km/h

[Eight_dollar]

sound more like you need and oil change and a syncro re-bed in done ( done during a road test )

Plenty of boxes have been fixed this way

[Andy_Mac]

Yea mines at round 2600rpm, bit of a PITA if you ask me, sits right where the primary starts spooling so any more than feather light acceleration stuffs any chance of good economy. Irrelevant if the box is going into a NA though.

[Marky]

Oh weird, work that out. Will have to see if code on my gbox actually matches the build tag I guess, always thought it weird when people said about 25/2600 in 5th

[Guest]

 Eight dollar said:

sound more like you need and oil change and a syncro re-bed in done ( done during a road test )

Plenty of boxes have been fixed this way

How is this actually done though?

[B4 2000]

 Marky said:

Oh weird, work that out. Will have to see if code on my gbox actually matches the build tag I guess, always thought it weird when people said about 25/2600 in 5th

Rev A & B (MY99 & 00) have the gearbox you said. C & D have a different box/not the same boxes as STIs.

[Nachoooo]

Same as evowrx here, I\'m curious as to how you\'d do that with a syncro?

[Eight_dollar]

its done by loading the sycro\'s against the "gate"

need to be done under road conditions that will allow the loading to be applied - in a situation where the sycro\'s are trying accelerate and decelerated against their gates

[Joker]

still not helping! BUT 3rd gear is always been a bit notchy in the GTB : I just learnt to not try and quick shift into it

[Guest]

 Eight dollar said:

its done by loading the sycro\'s against the "gate"

need to be done under road conditions that will allow the loading to be applied - in a situation where the sycro\'s are trying accelerate and decelerated against their gates

How exactly would one replicate that situation?

[jost]

Turbo gearbox is what i\'m about to do with my Non Turbo BH with a dodgy torque converter, In theory the Turbo gearbox and clutch setup will last almost forever being under stressed. You may be able to locate a standard non turbo box but it seems that for every one there is 10 turbo ones for sale, Hopefully it hasn\'t been thrashed though, you may replace the gearbox, clutch, etc just to find issues with the replacement box.