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Discussion Starter #1
What are some things i can do to help protect my tranny? I already have a new clutch , pressure plate and flywheel. Anything else?

I hear people talk about new gears? what do they mean?

Thanks
Tom
 

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gears, as in the 5 forward gears. stock wrx gears suck
 

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Discussion Starter #3
MidnightFLAT4 said:
gears, as in the 5 forward gears. stock wrx gears suck
YEa i know that but i always thought new gears = new tranny...

U can buy the new teeth? Im guessing there made differently and are stronger?
 

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I used to have an old Eclipse GST that I had to put in a hardened 1st gear. No tranny change was necessary, although it was a crazy beoitch and I ended up taking it to a shop to have it done. I was screwing around too much like a jackass dumping the clutch at high RPMs. I did it too many times until several of the teeth on 1st gear ripped off. The funny part is, it was only after I put in the hardened gear that I actually stopped doing the crazy launches. Go figure. :tongue:

Anytime you do a high RPM launch and shock the drivetrain, the clutch is usually the first component to suffer. However, if you have a beefy clutch which can clamp hard and effectively transmit all that power without slipping then it's only natural that whatever is next in the drivetrain better be up to snuff and able to handle all the power that is being thrown at it. In this case, it's your gears.

Unless you are planning/running a bunch of crazy horsepower or doing all kinds of crazy high-RPM launches all the time, you might be able to get away without one. I've heard of people putting hardened gears in for both 1st and 2nd but unless you're running a ton of power, I can't imagine how a hardened 2nd gear could be really useful. Then again, Subaru gears supposedly suck as MidnightFLAT4 said, so maybe several hardened gears would be justified.
 

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From this board I have read numerous times that gears that have been failing are a symptom of a transmission case that flexes too much. I know nothing about how it is flexing and I am hoping someone who does will chime in but it seems like we should be able to come up with some sort of brace to keep it from happening.

Anyone want to comment?
 

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I also want more information about the flexing of the tranny..

How does it flex?
Where does it flex?
How can it be prevented? (If we know where, how and why it flexes I'm sure the tranny can be modified/ reinforced at some points)

I'm planning to run kaaz gears in the wrx tranny..
A mechanic (I don't trust) told me that the flexing probatly came becuase of the helical gears that twisted the tranny when tourqe was added.. This would not be a problem on the straight cut gears on the kaaz (1, 2 and 3 gear)

What do the wrx guru's think about this?
 

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yeah if we were to find out where it was flexing, then somebody could develope a gauseting kit ir a trans brace.
 

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ALT+F4 said:
yeah if we were to find out where it was flexing, then somebody could develope a gauseting kit ir a trans brace.
I read about a yr. ago someone WAS trying to make a reinforcing thinga bob,
Dont know what ever come of it.

Shotgun
 

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Putting in a new clutch is not going to protect your tranny...if anything it will lead to its failure. The clutch is usually the "weak link" that allows some slippage. By making it stronger, something else is going to give...usually the gears.
 

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Yeah Usually Manufactures will build in less expensive weak links intentionally....this is not to screw you over r anything...its to actually save you...well try...but subie sorta made the gearset weak links on accisent instead of the clutch.
 

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Jack said:
What are some things i can do to help protect my tranny? I already have a new clutch , pressure plate and flywheel. Anything else?

I hear people talk about new gears? what do they mean?

Thanks
Tom
Yeah, the new clutch/pressure plate combo might shorten the life of your gears, if anything. But to help prolonge it, lot's of people use the stock wheels/tires, inflated pretty high (like 40psi), when drag racing, so that they can spin them decently. That way you "break" the tires instead of anything else. Also, don't go dropping the clutch left and right on a daily basis. Revmatching when downshifting can help as well.

You can buy a whole sti tranny (like v7 or something), and that should help with case flex and stronger gears, plus better diffs, but I don't know too much about that stuff. Or get a buffed up gearset like Kaaz, and I know some company is selling stronger tranny cases. Those two together would be pretty strong I'm thinking.

But for the most part, treat your car like a normal car like a normal car, and it should last you pretty long. Rally teams go through trannys like they're nothing, and theirs are awfully strong. Act like it's a race car, and you'll be changing parts out like it's a race car too.
 

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Re: Stupid question

Ira Weiny said:
Would an STI 6 spd fit in a WRX? In the wagon?

Is it any stronger?

Ira
Yes and yes, but you will need some other stuff besides the gearbox. ie associated wiring for dccd, shift linkage stuff and I think axles and rear diff.
 

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The case flexing is true, but not very well documented and not adequately analyzed. If anybody knew about it, it would be the engineers at Subaru. As for the weak gears... they arent chromoly, they arent forged, and they arent big. Doing any of the forementioned would make it hard for them to sell the car at the price they offer it at.

They had to cut corners to sell and make money. (Tires, 16" wheel, 2pot front brakes, manually retracting antenna, no hydraulic pistons holding up the hood, a lack of insulation between headliner and roof. The cost saving list goes on. Its just a shame that they market this car to people who are known to beat the crap out of their vehicles. People like me.

They say 5.4 seconds to 60 in the ads... and that was done by MT with a 5 grand tranny dump that smoked the tires thru 1st. Bottom line do this enough in any trans and SOMETHING will break. Nothing ever broke on mine due to a launch, just upshifts....
The thing thats funny is that i will probably baby my STi gears after 30k miles of beating the livin shiznissle out of my little wrx.
 

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when i get my WRX i will be doing some testing.....Hopefully i will be able to post enough finding that will produce a tanny strengthening kit from either me or somebody else.

I know there have been problems with the Shalack(sp) gearsets and the gearsets that are the same, but a different name. I need to do some reseach into the Kaaz Gearsets, and see if they are a option for higher HP cars or for agressive driving.

Has anybody tried Solid tranny mounts? these will be noisy as hell, but will keep flex down quite possibly.
 

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ALT+F4 said:
I need to do some reseach into the Kaaz Gearsets, and see if they are a option for higher HP cars or for agressive driving.

Has anybody tried Solid tranny mounts? these will be noisy as hell, but will keep flex down quite possibly.
From what I've heard the kaaz is good up to 500hp !? but more noisy since it's straight cut (only 1, 2 and 3)

I think I'll go with the kaaz gears and see how the tranny with wrx casing are holding up. I will not get the gears this year however so there will be some time to I can test the combo..

Have not testet solid mounts either, was thinking to put in some gruppe N bushings some day.
 

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i think one day i will pik one up from the junk yard or on ebay.....will see whats up! If it isnt Shuffle pinned, that might be a problem. also i will check about differential side loading the case and causing it to split....I have a few ideas for some possible problems...i will se when i get ahold of a tranny.....if anybody whats to donate a dead one...it will go to a greater cause!
 

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Re: Re: Stupid question

Chunks said:
Yes and yes, but you will need some other stuff besides the gearbox. ie associated wiring for dccd, shift linkage stuff and I think axles and rear diff.
Just wanted to mention (although some people know, for the benefit of those that didn't), that you'll also need the clutch and flywheel and driveshafts from the 6-speed. And not too sure, but I think the mounts too
 

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i've been quoted around $6000-$7000 for a complete STi tranny swap and all the necessary parts. This includes a rebuilt 6mt from a JDM 2.0L STi...the USDM 2.5L STi tranny won't fit I think.

MRT makes some nice gears for the WRX tranny case.
 

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that's incorrect.. either one will fit.. but the JDM has better 4th and 5th gear if your not looking for massive top end (greater than 155).

Also I just bought my JDM trans for 4000. This included the clutch, flywheel, diffs, trans, driveshaft, etc... everything except the rear 3.9 ring and pinion which can be sourced at the local junkyard for 150. And I'm doing installation w/ a couple friends.. so you can do it much cheaper than 6-7k should be less than 4500 complete.
 
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