6MT Master Swap Thread

One more update...the very new-looking R180 differential I picked up off of eBay seems to be leaking fluid (very slowly) from two of the bolts on one of the side plates. It's like one drip every few hours when the car is parked, but it seems to leak a lot more when the car is moving, because I find traces of gear oil sprayed all over my exhausts.

I'm really hoping this is fixable just by replacing the o-ring on that side, because short of a cracked housing, I can't imagine what else might be causing that sort of leak.

One more update...the very new-looking R180 differential I picked up off of eBay seems to be leaking fluid (very slowly) from two of the bolts on one of the side plates. It's like one drip every few hours when the car is parked, but it seems to leak a lot more when the car is moving, because I find traces of gear oil sprayed all over my exhausts.

 

I'm really hoping this is fixable just by replacing the o-ring on that side, because short of a cracked housing, I can't imagine what else might be causing that sort of leak.

That's the plan - I ordered a new O-ring and new bolts. I guess I could have ordered a new plate as well, but we'll see.

Worst case (short of a new diff, anyway), it's either gonna be JB Weld or Permatex.

Final (hopefully) update: pulled the diff and the side plate to put in the new o-ring.

Well surprise surprise, there was no old o-ring in there! I'm assuming that means that someone disassembled the diff at some point, which is not very reassuring.

Anyway, I haven't driven on it yet, so we'll see if that fixes the problem.

Question regarding the rear diff mount:

 

Can the '08+ STi aluminum rear diff mount be used in place of the Spec B mount?

 

From pictures, they look like they are very close in dimensions, but perhaps the outer ears are a bit wider in the STi.

 

I believe if my memory serves me correctly the answer is yes. I think shawn or someone used the sti mount

Hi all,

I just swapped to 6MT my Legacy.

http://legacygt.com/forums/showthread.php/legacy-swaped-gt-europe-158057.html?t=158057

Hope it helps!

zexauk - Nicely done!

The 4th Gen Legacy using the R180 Rear diff, needs a hybrid rear axle as you discovered.

You can source these as 2007-2009 USDM Legacy GT Spec B rear axles which are hybrid axles made to fit the R180 rear and the Legacy hubs.

And, you can also use the 05-09 USDM and likely EDM 4EAT rear drive shaft. You just need to change out the rear flange to match the R180 flange, otherwise it's a direct fit, no custom fabrication needed.

Thanks SBT!

I understand it can be a cheaper solution... I payed around 300usd for the 2 rear axles (+ ends coming form STI and Legacy that I already had).

It can be a good alternative in the future if I brake one...

This one for example?

https://www.summitracing.com/int/parts/aaz-66-7355/applications/make/subaru/model/legacy/year/2008/submodel/gt-spec-b

Thanks in advance!!

Well, after lookin around for the past few weeks, I found a good deal on the “4cc” version of the Forester STi transmission/r180 riff. Should be here in about a week. Time to start looking around for all the other bits I’ll need to get the swap underway. My 5spd has 122,000 miles on it and is starting to make a few noises in lower gears.

I’m really looking forward to not being at 3400rpm at highway speeds in top gear!

I've been getting my parts list together for the swap. I am going to attempt to get everything together for early may. The Transmission arrived with the diff, starter, some axles and shifter linkage. Since it's all out of the Forester STi, I am pretty certain the axles and linkage won't fit, so i'll have to source those. I need to look at the transmission closer to see if anything else on the list came included with the trans.

Here is the list. I am hoping Tema can chime in with the specifics of the Forester swap.

Transmission: JDM Forester STi "C" TY856WL4CC (2004)

Rear Differential: JDM Forester STi R180 Rear Diff

Clutch/Flywheel: Reuse Legacy 5-Speed Clutch/Flywheel (Recently Replaced)

Driveshaft: Legacy 4eat Automatic Driveshaft or 07-09 Legacy Spec-B Driveshaft.

Front Axles: Reuse Legacy 5-Speed Axles and Front Axle Seals

Rear Axles: 07-09 Legacy Spec-B Axles (28421AG03B) Axle Seals (806732200)

Shifter Linkage: 08+ STi or 07-09 Legacy Spec-B

Clutch Fork: 30530AA050

Clutch Release Shaft: 30532AA020

Clutch Slave Cylinder: 30620AA172

Clutch Hose:

Throw-Out Bearing:

6MT Rear Transmission Mount:

Downpipe Support Bracket: 44021FE030

Various Seals:

Various Fluids:

I've been getting my parts list together for the swap. I am going to attempt to get everything together for early may. The Transmission arrived with the diff, starter, some axles and shifter linkage. Since it's all out of the Forester STi, I am pretty certain the axles and linkage won't fit, so i'll have to source those. I need to look at the transmission closer to see if anything else on the list came included with the trans.

 

Here is the list. I am hoping Tema can chime in with the specifics of the Forester swap.

 

Transmission: JDM Forester STi "C" TY856WL4CC (2004)

Rear Differential: JDM Forester STi R180 Rear Diff

Clutch/Flywheel: Reuse Legacy 5-Speed Clutch/Flywheel (Recently Replaced)

Driveshaft: Legacy 4eat Automatic Driveshaft or 07-09 Legacy Spec-B Driveshaft.

Front Axles: Reuse Legacy 5-Speed Axles and Front Axle Seals

Rear Axles: 07-09 Legacy Spec-B Axles (28421AG03B) Axle Seals (806732200)

Shifter Linkage: 08+ STi or 07-09 Legacy Spec-B

Clutch Fork: 30530AA050

Clutch Release Shaft: 30532AA020

Clutch Slave Cylinder: 30620AA172

Clutch Hose:

Throw-Out Bearing:

6MT Rear Transmission Mount:

Downpipe Support Bracket: 44021FE030

Various Seals:

Various Fluids:

I had no issues to fit FSTi 6-speed with parts mentioned above. I didn't check numbers but I got my PNs from this thread which I mostly double checked.

I Recommend to renew axle seals in gearbox too.

Clutch hose I didn't change but I got complete assembly of slave cylinder together with transmission.

Seriously should consider STi-clutch too if you're above standard power.

Bigger standard clutch was one strong argument for 6-speed and I'm extremely happy with it.

5-speed clutch is a bit so-so while STi-clutch can take some serious torque and is supposed to have good longevity.

Only real problems I had with was aligning new clutch without tool.

I ended up cutting piece of clutch shaft from old damaged gearbox to use as alignment tool.

I have about 150miles on my 2011 STI swap and it’s fantastic in every way. It shifts very smoothly on Motul 300. The ratios are PERFECT for the back roads around where I live.

WHY DIDNT SUBARU OFFER THIS TRANSMISSION IN A LGT? Limited slip diffs are a total game changer. There are a few turns that I could spin my front-wheel if I powered out of, no more, the car just pulls. A few things to note:

OEM Clutch is holding my AVO380 stage 3 power with no problem. It is also a significantly lighter pedal than my 5MT FX300.

Full poly bushings in the driveline now makes everything a lot tighter and really didn’t add much noise. I already had all poly suspension/steering bushings so NVH was high to begin with.

STI rear cradle works fine with LGT.

WC Latewerks SS shift knob is awesome and beautiful, just like their 5MT piece.

The iWire ”plug n play” DCCD PRO kit is ANYTHING BUT plug n play. Basically every connector needed to be re-pinned (or just pinned in general). It was a pain in the ass but it all works fine in the end.

I still need to mount the DCCD switches and diff lockup LED indicator.

Does anyone have reccomendations on a short throw shifter?

The STi swap been putting a on my face for over 260k+

Spotted a 09 Subaru Legacy 3.0R LTD, 136k for $6,995. 1st thing I was thinking was swapping my 05 STi 6MT & matching R180 rear diff. From my total:rolleyes:, but very drivable LGT:cool:.

* Spec B gears for 2nd-6th (aka Rallispec's "high speed" 6MT gear ratio conversion)

So I am talking to RalliSpec about having them rebuild 05 STI 6 speed from Mike's (HAMMER DOWN) LGT. Since they will be taking the shafts apart for synchro replacement, I also asked them for a quote for that 2-6th gear change NSFW talked about.

Question is, does that change force me to get a different rear diff? I plan on swapping everything from Mike's car straight to mine. Already have the diff out.

EDIT:

Got answer from RalliSpec. Rear diff does not need to change if the 2-6th gears are changed. The quote however is rather steep.

So I am sitting on the decision to make now - do I pay almost $1400 for gearing change from standard STI 6 speed to SpecB 6 speed? Tranny from HAMMER DOWN's GT should be coming out tonight (I hope) and I want to have it rebuilt, this much I decided upon.

I am doing more highway driving than town driving (such is life in the woods), and will start my long weekends commute in the fall (~180 miles on weekend). So having engine at lower RPMs would be nice, I just don't know if the difference is so great that it's noticeable and is worth $1400.

The STi swap been putting a on my face for over 260k+

 

Spotted a 09 Subaru Legacy 3.0R LTD, 136k for $6,995. 1st thing I was thinking was swapping my 05 STi 6MT & matching R180 rear diff. From my total:rolleyes:, but very drivable LGT:cool:.

Mike,

did you end up switching to 5 speed NSS eventually? I drove the car around a little bit but not to a point of engaging cruise control. I will likely have the tranny out today/tomorrow.

Mike,

 

did you end up switching to 5 speed NSS eventually? I drove the car around a little bit but not to a point of engaging cruise control. I will likely have the tranny out today/tomorrow.

Yes, the 5MT NSS is installed.

IIRC @ 75mph, RMP's was 3000