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which are the strongest transmissions?


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anybody know which of which trannys are the strongest? (ie: hold up to the most torque and horsepower abuse)

 

I do believe that I've heard good things about all of them and bad things about all of them, like nobody can agree on anything. Does anyone know for sure?

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I feel comfortable saying that the new 6MT in the STi is probably the strongest. That is Subaru's first all-new transmission in 20 years. It's built to handle 300hp stock obviously, it has dual-cone synchros on ever gear except 2nd, which has triple-cone synchros. It's got its own oil cooler, too.

 

But if you don't wanna spend $7500 on a brand new STi tranny :rolleyes: , then you could look for a overseas gearset, literally dozens of people have WRX type RA gearboxes and the like in their cars here...

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Here it comes mikey :)

 

I disagree.

 

First of all the 6mt isn't new, it's been around for years. Also the trans between the ea and ej aren't the same so there's a new trans in less than 20 years.

 

Secondly an Automatic trans is stronger than an manual trans of equal build quality. That said any of the 4eats setup for turbo cars or the svx would easily handle more power than all the 5mts, as far as the new 5eat better than the 6mt, I'd say it's quite possible, but then again I don't know the internals of a 5eat. :)

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Here it comes mikey :)

 

I disagree.

 

First of all the 6mt isn't new, it's been around for years. Also the trans between the ea and ej aren't the same so there's a new trans in less than 20 years.

 

Secondly an Automatic trans is stronger than an manual trans of equal build quality. That said any of the 4eats setup for turbo cars or the svx would easily handle more power than all the 5mts, as far as the new 5eat better than the 6mt, I'd say it's quite possible, but then again I don't know the internals of a 5eat. :)

 

I'll disagree on the automatic bit all day long.

Answer me this, why do SVXs always seem to have failing automatics???? SVXs with dead transmissions (they only ever came in automatic for those who might not know) can be had for a dime a dozen across the country.

 

Also, you can take any EJ series 5mt case and install the Japanese spec STi type RA gear set and it will be just as strong or stonger than the US 6mt, plus a whole lot cheaper at around $1500.

 

Keith

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ok, so then, it seems that at least, the RA type gearset seems to be obviously liked.

 

oh, and nothing from subaru would run me what it would cost for you guys... I get 10% above cost on anything I get from any of the dealerships in town (because I'm special) which brings me to the next part, if anybody has parts that I'm in need of, and they plan on buying oem parts anyways, maybe we can make a deal. mwahaha.

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The new 6mt is a very, very beefey trannie by far the beefist manule trannie that is stock from subaru, even a 5mt with the RA gear set cant come close to the 6my beefiness. I have read over on nasioc that a couple members say subaru has rated it 550 ft pounds of torq, and there are alot of 400whp+ STi with no trannie problems what ever to make that 550 ft pound of torq rating seem plasusable. If you want a drag trannie i wouldent go with the 6mt, the gear ratios are to close and you will be shifting to many times in the quarter, but if your looking at a track day, every day driver i would definitly go with the 6mt if you have the money, you can pick them up for about $5000 used in good contdtion. If you want a purpose built drag trannie i would maybe look into a built 4eat, its a extremely strong automatic stock, you just need to keep it cool, but if your draging it shouldent be a problem. If your going to be putting out a huge amount of power (over 300whp) and want the 5spd to hold it i would get a beefier gear set that the RA one and have the case reinforced because it spose to twist under alot of load, althought the brand new 05 5mt has a gridle to help with the flex. Ive heard that the 5eat is a very light weight trannie for a 5spd auto which scares me beacause you need weight to have a strong trannie unless using extremely exotic materials which i dought subaru did, and it shares the typical 4eat oiver heating problem under extended hard use so i would go with a built 4eat out of the autos its cheap and its been proven.

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Well, for those that don't know, the STi type RA geat set is the Homoligated FIA racing gear set for Subaru. That means it is what is used in all FIA group N rally cars around the world. These cars routinely put out over 300ft. lbs. of torque to the wheels and the gears never complain. Not saying the 6mt isn't stong, but the 5mt with the type RA gear set will take a whole lot of power.

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Well, for those that don't know, the STi type RA geat set is the Homoligated FIA racing gear set for Subaru. That means it is what is used in all FIA group N rally cars around the world. These cars routinely put out over 300ft. lbs. of torque to the wheels and the gears never complain. Not saying the 6mt isn't stong, but the 5mt with the type RA gear set will take a whole lot of power.

 

The new Group Ns use the 6mt. And in group N i thought you really dident put out that much power, besids those guys are basicly always in dirt theres no traction to blow the trannie up. Look on Nasioc most will say about 275 whp is the max on RA gear sets.

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I'll disagree on the automatic bit all day long.

Answer me this, why do SVXs always seem to have failing automatics???? SVXs with dead transmissions (they only ever came in automatic for those who might not know) can be had for a dime a dozen across the country.

That's a very easy question to answer. Cooling. ATF is very sensitive to heat. If you overheat the fluid (which isn't hard), you'll cause damage to the internals of the trans. But that doesnt mean the actual transmission is weak. If you disagree think about other systems. Brakes for one, overheat the brake fluid and you'll end up with ****ty brakes, Coolant, overheat and you can crack a head. If for example you had a radiator the size of the 1.5l honda in the cooling system, how long do think one of our engines would last? Now tell me, if you just completely removed the radiator all together, how long do you think it'd last?

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That's a very easy question to answer. Cooling. ATF is very sensitive to heat. If you overheat the fluid (which isn't hard), you'll cause damage to the internals of the trans. But that doesnt mean the actual transmission is weak. If you disagree think about other systems. Brakes for one, overheat the brake fluid and you'll end up with ****ty brakes, Coolant, overheat and you can crack a head. If for example you had a radiator the size of the 1.5l honda in the cooling system, how long do think one of our engines would last? Now tell me, if you just completely removed the radiator all together, how long do you think it'd last?

 

Well, I don't know enough about the internal workings of an automatic transmission, but I do know that you are trying to compare apples to oranges. If the trans has poor cooling stock and fails it fails. Stock to stock the automatics in the SVX don't seem to hold up. Even in the first gen legacy they are the first big thing to go.

 

Also, it's hard to overheat the coolant. You can overheat the engine by not having coolant or a properly functioning cooling system. But once angain have a functioning stock cooling system and the engine will not overheat and fail.

 

Brakes, I'm not even going to get into it, but you'll be hard pressed to overheat brake fluid even with some semi-metallic performance pads on.

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The new Group Ns use the 6mt. And in group N i thought you really dident put out that much power, besids those guys are basicly always in dirt theres no traction to blow the trannie up. Look on Nasioc most will say about 275 whp is the max on RA gear sets.

It all depends on what year car you're running. Anything pre '04 is defenitly the 5speed. Not sure about things since the STi and the 6mt hit North America.

 

As for power, be careful what you really mean. All Turbo rally cars are forced to run restrictors. That means the cars don't produce a lot of HP. They do however create tons of torque. a properly tuned WRX motor running an FIA 32mm restrictor will put out just over 300 ft. lbs. of torque to the wheels. And yes, most rallies are dirt, but there are tarmac rallies.

 

As for NASIOC, just like hear you can't blindly go by what someone on there says. You get a lot of people over there that do nothing but read this and that but have no real experience. 275Whp is a lot of Flywheel power but I think it can take a lot more. I've been around lots of rally cars including our rally car that destroyed it's stock WRX gear box shortly into it's second rally. We put the Type RA gear set in and we've put it through a ton of abuse with no problems.

 

Also, here is a link to a really good east coast rally prep company that sells some 5mt gear sets. http://www.rallispec.com/product-gearset.htm They don't really say what the type RA is good for, but it's what they usually install for rally cars.

 

Keith

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Well, I don't know enough about the internal workings of an automatic transmission, but I do know that you are trying to compare apples to oranges. If the trans has poor cooling stock and fails it fails. Stock to stock the automatics in the SVX don't seem to hold up. Even in the first gen legacy they are the first big thing to go.

How is this comparing apples to oranges? They're both transmissions.

 

So you're saying since it has bad cooling to begin with and it fails that makes it a poor transmission, now correct me if i'm wrong but you're suggesting to swap out all the gears and **** from the 5mt tranny to an entirely different gearset. How does this not make a 5mt a poor transmission? You're basically saying that a stock 5mt is **** but if you change the gears you'll have a good tranny, and that's acceptable, but it's not acceptable to add an auxillary cooler and have a better than stock trans? Hell, if you give a 4eat a level 10 build there will be NO question of the strength of it, but I didn't suggest that did I? I was trying to stay within the constraints of a stock trans.

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There are many levels of transmissions that subaru has built over the years.

 

In general terms the STi-RA has had the strongest gearbox for a given year, with the normal STi just behind. The WRX is a step down from the STi's and the naturaly asperated cars another step down.

 

In specifics the 6spd is hands down the strongest stock gearbox subaru makes. It shares little to nothing with the 5spd manual. Some issues with it though are that its much heavier than the 5spd manual and it consumes some 15+ WHP more than the 5spd manual at 7K rpm.

 

Next up in strength is the Forester XT, Legacy GT, and Saab 9-2X transmissions. These use a revised case for extra strength. No reports on what the exact guts are on these but expect the FXT and LGT to run the equvalent to the 5spd Type-RA boxes. The saab may just use WRX level internals given its low stock torque.

 

Next down are the STi 5spds from Japan.

 

Below that are the WRX gearboxes.

 

etc.

 

More over there is a definite trend of the newer the box the stronger it is as nearly every year subaru makes upgrades and evolves the design.

 

 

Oh and the GPMoto forester put 420WHP and 400+ ft-lbs through the stock FXT transmission. My STi has seen the same powerlevels for well over 10K miles and is like new. Stood up to well over 50 off redline launches at the drag strip too.

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How is this comparing apples to oranges? They're both transmissions.

 

So you're saying since it has bad cooling to begin with and it fails that makes it a poor transmission, now correct me if i'm wrong but you're suggesting to swap out all the gears and **** from the 5mt tranny to an entirely different gearset. How does this not make a 5mt a poor transmission? You're basically saying that a stock 5mt is **** but if you change the gears you'll have a good tranny, and that's acceptable, but it's not acceptable to add an auxillary cooler and have a better than stock trans? Hell, if you give a 4eat a level 10 build there will be NO question of the strength of it, but I didn't suggest that did I? I was trying to stay within the constraints of a stock trans.

 

First off I don't want to argue so lets not. I honestly don't know enough about automatics to say that an automatic can't be strong, and for that matter yes I agree that they can be strong. (Look at american drag cars, that's strong)

 

That said,

#1 the STi type RA gear set came in a stock car made in Japan, therfore it is a stock trans. You can call your local subaru dealer and if they are willing to talk to Japan they can get the parts.

 

#2 I never said the US stock 5mt is bad. It holds up to abuse well and will hold a decent amount of power without any problems. Lots of people have put them into their SVXs when the automatics has gone.

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