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Discussion Starter · #1 ·
I'm having trouble finding information about transmission swaps to 6MT transmission that are not sti (Spec B).
This post is about 75mm (TY75...) split case transmissions only

I currently have a 2005 Legacy Outback with a 5MT TY757VCABA 5 Speed transmission (4.111FD). I've always wished it had a 6 Speed, but I thought the only way to do that was a Spec B transmission which is way more involved/expensive than I wanted to tackle.

I recently discovered that Subaru made a TY75 split case 6MT from 2010 - 2014 (Gen 4 only I think). Thank you to the guys at RalliSpec. https://www.rallispec.com/downloads/Transmission ID Chart_Public.pdf
Unfortunately the list doesn't go past 2011 so I'm having trouble finding detailed information on 2012-2014 models. I've only found 1 other person who's considered this swap, but I don't know if he was successful.

I believe there are 3 (or more) 6MT YY75 transmissions that have the same FD as mine.
TY756WCAAA 10-11 Legacy Turbo
TY756WLAAA 10-11 Legacy NA
TY751VHDCA 13-14 Legacy NA

Does anyone know if there are other transmission models that fit the same criteria?
Is this swap a drop in replacement?
If not how much will I have to modify?
It appears that Subaru went to a cabled shifter at some point. Will that mate up with my current shifter or will I need to find a newer shifter?

Thanks
 

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2001 Outback Wagon 3.0 VDC
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388 Posts
One thing to note about the 2010 and up legacy/outback is the engine mount system, the 2005 has engine mounts on each side of the bottom of the engine, the 2010+ has the mounts actually attached to each side of the transmission, not the engine, so I dont think it would be a straight forward swap going this route.

Other options to consider might be the 6 speed from a crosstrek, the mounting system is the same as your 2005 and its the same style transmission (non STI). This is also cable shift though so you will need to replace the shifter assembly too, and the rear diff to match.
 

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Discussion Starter · #3 ·
I thought I'd follow up on this in case anyone else wanted to try this swap. I just finished, and it went about as smoothly as one could expect.

I bought a used TY751VHDCA (32000AK090) with 8k mi from 2014 Outback 2.5i NA. I also grabbed a used shifter/cable assembly out of an 2015 STI.

I was concerned about a 2005 clutch/flywheel/starter all fitting properly on the new trans, so I bought new ones for the 2014.

Everything bolted up perfectly (including the existing trans mount) with a few exceptions.
1. The new shifter is a clam-shell that bolts through the body. I had to drill 4 holes around the existing opening to bolt through.
2. The exhaust mount interfered with the new shifter linkage. I had to cut away the top of it with a jig saw.
3. several of the wire management brackets are different, I just used whichever ones from either transmission that worked best.
4. The I had to modify the support for the air intake box, and connect it to a different place on the trans.
5. The leather gear shift cover needed a little modification.

All in all, this went way easier than I expected, and I'm pleased with the result. My total cost was about $1,700
 

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1998 Legacy Outback, 2.5 DOHC, 5 speed manual
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Great results and thank you for sharing! I've been searching for info on swapping the split-case 6MT into a 5-speed car and there is not much out there.
 

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2006 Outback 2.5i manual
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Thanks for this info. How do the gear ratios feel? Are gears 1-5 essentially the same with just a 6th being taller? Or did Subaru shorten 1-5 compared to the 2005 2.5i gearing...?

I'm also looking for a 6spd swap, but I assumed the Spec B was the only way to go. Though I do like the idea of getting an LSD in the rear, even if it is just a silly viscous diff.

Either way, thank you for that chart. I lazily looked for something like that a while ago but failed. Haha.


Edit: for those who are interested, I used a gear ratio calculator to compare the 2006 USDM Outback 2.5i 5spd to the 2006 JDM Spec B Outback tranny...

USDM 2.5i
Font Rectangle Parallel Number Screenshot



JDM Spec B
Rectangle Font Parallel Number Screenshot




2nd gear is a TINY bit shorter. 5th is significantly shorter, and of course 6th is taller than our 5th. That said, the JDM 6spd is nothing special, IMO. I was hoping for a shorter 1-5 with 6th being taller than our 5th, but that's not the case. You'd really only be getting it for taller highway gearing, nothing else.
 
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