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WRX Hatch gearbox


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Hi everyone, lately i have been experiancing some problems with my hatch WRX.


Symptoms are:

1) Hard to engage reverse, takes several attempts

2) Sometimes pop out of first gear

3) When changing gear i get a vibration through the pedal when it engages


Whats the cause and solution? Do you think the gearbox needs to be rebuilt? If so i would love to go STI 6 speed but seems like a lot of money.

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Have you checked the fluid level as a starting point?


Not sure if the 5 speed box's are the same as int he hawk but if so they are pretty bullet proof and theres a few cars running 450 on em without issue

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I hope not. Was going to look into getting the gearbox refurbed before i move to the ring as it will be lapped daily so would like the peace of mind.

What clutch kits do people reccommend? And is it worth doing a flywheel aswell ?

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If your gonna be tracking it i would seriously consider going down the 2.1 closed deck block route and supporting mods, fuel system (swirl pot) oil cooler, front mount, syvecs etc etc

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Essentially the 2.5 is a bored out version of the ej20. I think the pistons are 99mm (don't hold me to this) so means that the block isn't as strong due to the walls being thinner around the pistons, you could get the block pinned in the winter

Sent from my SM-G850F using Tapatalk

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Track work is very different to road work, temps, pressures etc etc are all a massive step up.


The bores/liners on the 2.5 are not very strong when compared to the 2.0 and being open deck they are prone to flex, ovaling and splitting.


this is my 2.5 block being preped for machining and then converting to closed deck,




compare the bores to this,




Also the head stud location isn't ideal.


As said mine is being converted to closed deck,




It still has the same bore and wall thicknes, but is stronger due to the conversion.


There are also alot of other considerations to consider as mentioned, heat is a big biog issue on subaru's when drive hard, oil temps can easily take out an engine. Zen found this out when they cooked their engine in japan time attack the first year over there), that was a purpose built engine and it still fried itself due to 130 degree oil temps.


If your serious about using it on the ring regularly then i suggest you find a tuners whos well versed with race cars and speak to them about best route. Bear in in mind it wont be cheap

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So you are closing up the water jackets?


not really, when you look at the head end its not so open, if that makes sence lol




the biggest improvement is the restraining of the top of the liner/bore

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AS performance charge £450 + delivery for the conversion, give alyn a bell. Bear in mind its a proce for hte conversion, not inc the block.


Mines going else where but its just becuase scoobyclinic uses a different machinist and its being done through them.

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  • 4 months later...

Getting back to the gearbox issues ;) . Mine too is usually difficult to get into reverse and occasionally 1st too. I've changed the gearbox oil for castrol fully synth and the clutch fluid. Any idears? The gearbox oil is a bit over the top line on the stick. Would that do it?


Thanks in advance


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