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Transmission Options to Replace 6MT


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Yeah, there are aftermarket DCCD controllers. That would probably be a lot easier than trying to jam our center diff in there.

 

SI drive is a moot point for the transmission. That just controls the throttle/engine maps, doesn't really do much for the transmission afaik...

 

Mounting the trans and getting the shifter arm to line up are going to be the toughest parts of the swap. The rest isn't going to be a cakewalk compared to that.

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I mean, if you're going to that much effort to swap the transmission, you may as well go ahead and grab the standalone DCCD controller. You know, for a more robust center diff for doing doriftos in snow-covered parking lots. Go big or go home, right?

 

 

Meanwhile, OP is silently shaking his head, wondering why the hell he asked us for advice...

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The diesel version is just as strong (read "weak") as what we have now, might as well use a replacement or rebuild.

 

There are only two transmissions I would bill as stronger, the 5eat (iffy) and the STI 6mt. Maybe arguably the 4eat could be built stronger, but still 4 gears wont cut it.

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The 6MT for the EE20 has completely different gear ratios that are suited to the much lower RPM of the diesel engine.

 

 

Sent from my ZUK Z1 using Tapatalk

 

Not completely different

 

diesel: 3.454, 1.750, 1.062, 0.785, 0.634, 0.557, 3.636 fd 4.444

 

legacy: 3.454, 1.947, 1.296, 0.972, 0.780, 0.666, 3.636 fd 4.111

 

n/a leg: 3.454, 1.947, 1.296, 0.972, 0.825, 0.695, 3.636

 

I would bet with the higher final drive the diesel transmission would make a great cruiser and probably be a bit quicker to 60 with a longer 2nd gear.

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So I'm currently planning on ordering a used tranny off ebay for just over a grand. Trying to determine if the 2.5i will in fact work fine. I know it won't be any stronger. Does anyone know how the transfer ratios compare? I see that the 2.5i and GT both have the the same rear diff ratio, but the GT diff is nearly twice as much. I'm not converting to AT. Planning on getting mine back on the road ASAP and tearing open the blown tranny to build up with straight cuts 1, 2 and maybe 3 and upgrade with billet shift works and whatever other goodies I can.
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The final drive ratio is the same for all legacy models, so be sure it is a legacy not an outback which has a 4.444 compared to the legacy 4.111.

 

Get a hold of acumenhokie and see if his shop can replicate those blast plates otherwise you are just going to blow a tranny with more expensive gears in it.

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Looking at the vacation pics, the front and rear diffs are both 4.111 on the Legacy 2.5i (they're 4.444 on the Outback), transfer ratio 1.000 across the board. Far as I can tell, the only difference between the 2.5i and GT transmissions is the 5th and 6th gear ratios, everything else looks to be the same.

 

Let me know if you need a copy of the vacation pics, I might know a guy...

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The gear determination threshold tables are known and if not yet defined for your ROM it's not a tall order. Change the gear ratios or even tire height and these should be adjusted. I made a spreadsheet to calculate these values if anyone wants it.

As mentioned, no CANbus issues doing MT/MT swaps.

Si-Drive is irrelevant.

TY856 transmissions are available without DCCD and aftermarket controllers are available off the shelf if desired.

 

My feeling is that if you broke one trans you'll break another, and some upgrade is needed. Remember that lowering gear ratios reduces transmission load and vice versa. Taller ratios for cruising sound like a good idea but in hard use the trans will be more prone to failure.

Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs.
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So I blew my tranny in my 2010 LGT. Looking for options for replacements that will be as strong or stronger than the 6MT that came in the GT's. I've seen mention of the 2.5i 6MT being the same with just a shorter 5th and 6th gear, but nothing that seemed very convincing, proof, or first-hand experience/confirmation. These are much more affordable and easier to come buy with low miles. Also, does anyone know if the transmission for the diesel EE20 the same as the 6MT on the GT's (http://www.boxeer.com/ee20_parts)?

 

The diesel has the following ratios:

 

1 3,454

2 1,888

3 1,062

4 0,785

5 0,634

6 0,557

 

And a 4,444 final ratio.

 

However I'm not sure if the final ratio has changed over the years.

 

But if you want a new 6MT, maybe you should look for a STi box with DCCD?

 

And the 2.0i has the following ratios:

1 3,818

2 1,947

3 1,296

4 1,029

5 0,825

6 0,738

453747.png
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The diesel version is just as strong (read "weak") as what we have now, might as well use a replacement or rebuild.

 

There are only two transmissions I would bill as stronger, the 5eat (iffy) and the STI 6mt. Maybe arguably the 4eat could be built stronger, but still 4 gears wont cut it.

 

The HT CVT could also be an option, but I imagine that it would be "fun" to make that work in integration with the engine.

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The HT CVT could also be an option, but I imagine that it would be "fun" to make that work in integration with the engine.

I don't think any automatic is an option in our cars, ;)

 

Sent from my SAMSUNG-SGH-I337 using Tapatalk

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The HTCVT in the WRX's are having issues beyond stage 1 mods, I would guess a 5th Gen LGT is going to have issue as well at stage 2.

Yes, and that's ignoring the fact that the MT ECUs don't even have a hardware capability to communicate with the TCU, as in some pins are missing from the interface, let alone the CANbus addresses needed to get that job done. AKA, a really dumb idea.

Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs.
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I'm a spirited daily driver. Don't beat hard on it but don't baby it either. Take it to the drag strip once or twice per year. I just got e-tuned on E85 and should be around 325hp/375ft-lbs.

 

aaaaaaaaaaand this is why your transmission is dead.....it's fine to occasionally drive the car hard, but not constantly....

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aaaaaaaaaaand this is why your transmission is dead.....it's fine to occasionally drive the car hard, but not constantly....

The pile of timeslips I pulled from my glovebox before selling my GT disagrees with this statement. :lol:

 

Only slight issue my 6MT had was a little grind going into 5th gear, and 5th was never touched at the drag strip. :cool:

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I'm a spirited daily driver. Don't beat hard on it but don't baby it either. Take it to the drag strip once or twice per year. I just got e-tuned on E85 and should be around 325hp/375ft-lbs.

 

Do you have an aftermarket clutch?

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