2010+ Legacy Trans - 6 speeds in the 5mt case

[Rasmus]

In 2010 Subaru introduced to the American Market their 6 gear manual transmission from their European diesel lineup. It was a engineering effort to to fit 6 speeds plus reverse into the old 5 speed case and be able to take all the torque a diesel can generate.

This 6 speed is not at all the 6 speed from the STi. It's offered in the 2010+ Legacy GT, Legacy, and Outback. It's cable shifted making it more adaptable to an 818 project. The dimensions are the same as the 5mt that Factory Five is basing the 818 around.


You can see the cable shifters flopped forward.

It should fit.

There is one difference: The WRX (02-07 at least) have a speed sensor on the trans. The LGT took speed from the wheel sensor IIRC. You can add a sensor to teh LGT trans (friend did it when he swapped a WRX motor into a 2.5RS) but you have to drill into the case and add a plastic speed gear. Not sure all that it entails.

Here's the gearing:
Gear Ratio -------- Top speed (mph) assuming 245/40R17 tires and 7250 rpm limit
1st: 3.454 --------- 35
2nd: 1.947 --------- 62
3rd: 1.296 --------- 93
4th: 0.972 --------- 123
5th: 0.825 --------- 145
6th: 0.695 --------- 173
Final: 4.444:1

That's a very short first gear, extra tall 6th, and a beefy final drive.

[narkosys]

that is an interesting find. it would make having a 6 speed in the 818 much more doable. Thank you for this information.

P

[timmy318]

My question is would it be able to handle the power of an STi engine or would it even fit (last part is probably a stupid question but I'm a newbie so help me out here)!!!

[bazza]

Just bare in mind that these boxes are weak like any other Subaru 5 speed and it's due to the design. Look at a 6MT case and you see the structural differences - the load is supported in a completely different way plus if you've ever rebuilt a 5MT or 6MT you'll see the gear size differences - the Legacy / STI 6MT's are about twice the size - not to mention the oil pump in some 6MT's.

[Rasmus]

Thank you for this information.

You're welcome. But credit should go to philly15 and Mechie3 in another thread. I read what they typed and I knew that this transmission would derail the topic in that thread.

My question is would it be able to handle the power of an STi engine.

That's got to be the hottest, most debated, topic on this forum. Merciful fates be with you. My opinion: yes.

[flynntuna]

So that's were all the pepsi pallets went. LOL

[Zodiac]

yea basically would it handle high power applications but since it is designed for diesel then I would assume yes. I wonder if you can also swap out the final drive to a 3.9 to get higher speeds from each gear. Also how would swapping the transmission effect the speedometer? And finally why are subaru transmissions so expensive for rebuilds >:/

[timmy318]

Here it is.... For $1,700 it's yours!

[PhyrraM]

Due to the extra-gear crammng that Subaru did, I doubt that the same 2WD conversion kit that the 5 speed uses will work, nor have I seen any company offering them for the non-STI 6 speeds.

Just somethig to keep in mind when considering this transmission......

Also, keep in mind that generally a lighter car can make do with fewer gears (assuming the top gear in each is about the same ratio). In the 818, I see a 6 speed as mostly "bragging rights" (at least until the 5 speed is proven unworthy in a few actual builds)

[bromikl]

All I know is I want TALL gears. I want to cruise in 5th gear at 70 MPH and 1700-2000 RPM.

[HelluvaEngineer]

All I know is I want TALL gears. I want to cruise in 5th gear at 70 MPH and 1700-2000 RPM.

This is what I want as well. If you could make this transmission work, you probably would not even need first gear.

[Turboguy]

All I know is I want TALL gears. I want to cruise in 5th gear at 70 MPH and 1700-2000 RPM.

Be careful what you wish for.


I drove that way the last few years in my STi. The reward? A very badly carbonized engine, and pinging in the extreme. These things run pig rich from the factory, and I found out the hard way



Great find by the original poster. I wonder, as others have, if these will be more difficult to convert to 2WD than the standard 5 SPD? Hopefully not!

[blueoval_bowtie_guy]

My '07 Legacy GT was, IIRC, spinning around 3000-3500 rpms at 70 mph. It seemed like any RPMs below that range required a downshift whenever I encountered a hill.

[rjh2pd]

My '07 Legacy GT was, IIRC, spinning around 3000-3500 rpms at 70 mph (auto). It seemed like any RPMs below that range required a downshift whenever I encountered a hill.

yeah my 03 legacy is at 3000 going 75 i think. For a big hill it does need to down shift, but with this light of a car you wont need to. Also if you are using the turbo'd engine you really wont need to. disclaimer, running lower rpms for the turbo means your further from boost but that is something i would give up to go 75 at 2000 rpm since you can down shift.

[Subarugears]

This transmission is as simple to convert to 2WD/FWD as the 5 speeds. Remove the center differential and the transfer gears.
Fit a 2WD locking Subaspool (we already make the correct Subaspool for this 6 speed, which has a different spline to the 5 speed).
Fit a 6 speed Subaplate to close off the back of the transmission and seal off the shift rod.

What Bazza said about Subaru transmissions is incorrect. They are not weak. They suffer from poor drivers putting 400kw through them on 7000 rpm launches in 4WD clutch dumps, then smashing them into second gear. Used correctly, in a lightweight chassis and in 2WD you would find it near impossible to break one, expecially a late model one. Also, there is not much difference between the STi 6 speeds and late model turbo 5 speeds and this split case 6 speed in terms of gear width and strength. The STi's do NOT have double the width. The first and second gears on these split case 6MT's are very wide and strong in order to cope with the 350nM of torque of the turbo diesel. You will not easily break any of these transmissions with a turbo petrol engine.

[Turboguy]

Awesome news!


Does this 6 spd use a different "Subaspool" and "Subaplate" from the 5 speed version? Out of curiosity, how much would the parts you'd need to convert the 6 spd mentioned above cost?

[Subarugears]

This split case 6 speed buses a different Subaspool to the 5 speed - only because some of the splines are different.
I have done some in the past and am about to do another production run. They will be $200 shipped to your door worldwide.
Subaplate is the same as the 6 speed version but requires a billet section to bolt over the top of the partial shift rod that's protruding.
I have some in stock already - all billet and bling. Price will be $200 shipped to your door worldwide.

I honestly don't know why you would all want to go 6 speed though. You don't need that many gears and you won't break a decent turbo transmission when in 2WD and in a light car. Stop kidding yourselves you are not making 1,000 hp and the 6th gear is just a further overdrive for fuel economy in heavy Subarus.

Stick with the STi 5 speeds or Legacy turbo 5 speeds that are cheap and plentiful. They have real nice ratios. These 818's are going to be awesome!

[narkosys]

I live in the middle of nowhere in the mountains and as I plan on making this my DD, it will do a crap tonne of hwy miles. A 6MT would be nice option for me to be able to think about.

P

[Turboguy]

Life would be even better if Subaru put this transmission behind their EZ30 or EZ36 flat-6 motors. Then my driveline could come from a single car!

[Xusia]

Yeah, no doubt! That would be my dream as well.

[Turboguy]

Perhaps if we start a Facebook group and promote it, Subaru will comply


My other half works at Shoppers Drug Mart. Their customers were annoyed by the fact that the store started playing Christmas music November 1st. So they started a Facebook group to promote the idea of turning it off. And the retailer complied almost immediately. As of December 2nd - still no in store x-mas music. The employees are ecstatic!

[C.Plavan]

Just for fyi-
Outback XT 5speed gearing/speed/rpm drop/
Gear MPH RPM
1 16 3000
1 42 7500
2 42 4800
2 67 7500
3 67 5200
3 97 7500
4 97 5600
4 129 7500
5 129 5700
5 181 7500

[Turboguy]

Isthis with the 4.11 or 4.44 final drive, Chad ?

[Rasmus]

The Outback XT runs a 4.444 final drive in stock form.

[C.Plavan]

Yes that was 4.44.

Here is 4.11 with the same tire diameter of 24.8 inches.

Gear MPH RPM
1 17 3000
1 46 7500
2 46 4800
2 72 7500
3 72 5200
3 105 7500
4 105 5600
4 140 7500
5 140 5700
5 196 7500

[Subarugears]

Life would be even better if Subaru put this transmission behind their EZ30 or EZ36 flat-6 motors. Then my driveline could come from a single car!

In some parts of the world they do. Most EZ30 cars are auto however.. :-(