Jump to content

5MT to 6MT swap 2008


Recommended Posts

Hi all, just looking to gather all the info for the swap from a 2008 spec b 6MT from a donor car I have into a 5MT 2008 gt. Organizing my thoughts here and any walkthrough information. I did see the 6MT sticky here but I'm specifically looking for this swap, should be simple as I'm not dealing with STI trans and the cars are very similar. I am going to be swapping motor as well as spec b suspension into the car too, so I will likely swap ecu in as well and get dealer to flash the VIN after, as the spec b has a better motor (hail damage parts only car, runs fine, no CEL).


I will likely replace the clutch with an upgrade just because I will be getting in there anyway to at least inspect it.


So to populate the list of parts I will want to swap I just want to break it down, drivetrain etc. Also anything you suggest I replace besides clutch while I have the engine and drivetrain out? Belts etc, without adding too many variables to the swap?


Thanks in advance!


Sent from my Pixel 3 using Tapatalk

Link to comment
Share on other sites

  • 4 weeks later...

Thanks I read that but it's not quite all in one place. There's a lot of talk about the other options for transmissions, not quite as specific in my case. I am playing with the idea of other parts that I might as well change at this point while I'm pulling the engine. Not shooting for big power at this point, but things that come to mind are new belts, new engine wiring harness, new hoses, possibly oil pan upgrade with pickup (killer b), possibly an air oil separator... Anything not requiring a tune or access port at this point. Suggestions welcomed.


Sent from my Pixel 3 using Tapatalk

Link to comment
Share on other sites

It should be a pretty straight forward swap. all parts from the 6mt driveline will fit into the car the 5mt came out of.


The shifter boot plastic piece is a little different too, but that is a easy piece to swap out.


Use Motul Gear 300 for both the 6mt and R180 rear diff.


You might want to look into a STI FW and clutch kit. Should have more better options...yeah I just said that...LOL


Lakewood CO, how close are you to Cryoperformance ? Dave post on here from time to time. Check him out for help if you need it.



305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.


Engine Build - Click Here

Link to comment
Share on other sites

  • 2 weeks later...

Howdy from Lakewood! I work up there, just south of the Federal Center on Kipling.


Recently swapped in a 2012 STI trans, so its relatively fresh in my head. The stickied swap thread above is a great resource, but you're right - its a bit dense. Took me quite a while poking thru and gathering information I needed, but it is all there. Check out my posts Here and Here for some of what I was able to gather. Not all of it is applicable, but tidbits help.




If you've got a donor car, then yeah, should be a pretty straightforward affair for drivetrain stuff.




As far as what to do while the whole thing is out, well that gets to be a real long list real fast. Sky is kind of the limit, or at least your budget is.




New clutch is definitely in order. I've been a big fan of the SouthBend clutches. Running a stage 3 daily now, which is way overkill for your needs, but I'd trust and recommend anything in their lineup. Lots of options out there, though. Exedy Stage 1 I've heard good things about. Since you're in Lakewood, once you have your resurfaced flywheel and new pressure plate in hand, take the pair over to Doug's Balancing and have him balance it. 60 bucks to do it. I won't do a clutch on my own vehicle without balancing, now.



I'd recommend replacing the various shifter bushings while its easy. Whiteline makes a kit that works well, includes the front bushings and the rear stay bushing, part KDT957. I didn't use the Whiteline rear stay, ended up with a 'Group N' from the dealer. Either one will work, but they all help eliminate slop in the shifter assembly.




For sure get the Whiteline rear diff positive power inserts, part KDT903. Made a huge difference in shift feel - eliminated all kinds of rubber banding on clutch engagement.



I replaced all my mounts with Group N mounts from the dealer. Engine, pitch stop, and trans mount. Highly recommended. Minimal NVH added, lots of slop eliminated.




Engine side, you can go wild with it, if you want to. Use OEM parts as much as you can.


Definitely rear main seal. There's some other seals back there on the block at the air/oil separator you might consider if they're showing signs of leaking.


Timing belt will never be easier than with the engine on a stand. Use an Aisin Kit, TKF-004. Skip the Gates kits.


Do the spark plugs, even if they've been done.


Reseal the valve covers. Use OEM Subaru gaskets, they're worth it. Dont forget the spark plug tube seals and the half moons.


Front crank seal.


Get some new exhaust gaskets, Grimmspeed makes some nice double thick turbo gaskets. Make sure your turbo is in good shape while its accessible, no shaft play present.


Get a new turbo oil drain tube.


Check all the coolant lines, at the turbo, the reservoir, the crossover pipe down front, and the lines that connect it, all those little rubber "L" pieces.


Check the turbo inlet tube, they get greasy and soft and can tear where it clamps to the turbo. Now's the time to replace it.


Get a new PCV valve assembly, now's the time to replace it.


There's a theme here, lol, 'Now's the time'.


Consider replacing the upstream Air/fuel sensor - they age and can get less responsive, which affects how it runs.




I'm running the Killer B oil pan/pick up/baffle package, and its definitely nice, but it sure is pricey. Might be overkill for a stock power build, but you can never say no to more oil capacity. Moroso makes a nice steel pan thats quite a bit cheaper. You can stick with the factory pan if you want to, but I would at least do one of the upgraded oil pick-up tubes. Factory pick up can crack and start sucking air. Grab a tube of either the ThreeBond sealant from Subaru, or FIPG 103 from Toyota to reseal all the things on the motor/oil pan/etc. Better than the store bought stuff.




Like Max said above, once you're all done with the mechanical stuff, go see Dave over at Cryotune Performance in Arvada for a tune, or find him on here. Get yourself an Accessport from him. I know you said you're not going for power, but they allow you to get off the factory tune, which is far from ideal. He'll get it running way better and safer than factory, even if you're not trying to make power. He's a great resource for information, and a great tuner - dyno or e-tuned. He tuned mine to 400whp on his dyno. More importantly, its safe.


Idea -- skip the KillerB pan, get a new OEM pan, and put that money towards the Accessport! Perfect! lol...




Anyways, that's a really long way to say, there's lots of things you can do! Keep reading here as much as you can, it's all been done and written about at some point, somewhere. PM me if you have specific questions, or if you're ever in the Kipling/Kentucky area, I work at one of the auto shops there.

Edited by RckyMtnGT
Link to comment
Share on other sites

Thanks, I finally just saw these posts on here and hilariously I've already done 90% of what you both mentioned aside from clutch and seals. I've been in touch with Dave and I bought some whiteline stuff and the killer b package from him. Buying a bunch of whiteline for the rest of the suspension and kartboy for shifter from RSD. Haven't got the iag AOS yet, probably getting clutch kit from ZF. FabFaction pitch stop. New hose kit from GPlus on Amazon, not splurging there. Also intake to tgv gaskets by IAG from RSD as well as Redline 5w30 and OEM filters. GS exhaust gasket kit and donut ring. I've already got laser iridium ngk Sparks ready to install. I need to service the CV boot at least and I'm looking at just cleaning up and reusing what I can for that. As far as differential I haven't considered servicing those so much, maybe after I swap the suspension. Already have the Aisin tb kit with pump coming from Amazon, I'll see if their pump gasket is good vs oem. As far as seals any part numbers would help. Also I'm looking into swapping the stock map for 6mt with a vag com cable and rom raider. Was considering replacing the whole engine wiring harness with new because I hate old plastic clips. $240 was the cheapest I've seen for that from Texas OEM dealer online. Somewhere else new I'd consider. Already bought oem coolant and new OEM thermostat. The list goes on from here. I'm looking for a local place that might press the new bushings on for me too if you know one.




Sent from my Pixel 3 using Tapatalk

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Create New...

Important Information

Terms of Use