2012 LGT 6mt into a 2005 LGT 5mt

[Infosecdad]

It's in and it fits

 

I've seriously questioned my sanity in the last 48 hours for trying this.

 

Side Note: Long COVID SUCKS! I've lost so much muscle mass over the last 16 months of not being able to move. I'm used to just manhandling stuff into position, I can't do that right now. Several times muscles just gave out and there may have been some weeping and gnashing of teeth. Last night I was trying to get the tranny to mate with the engine and had a nice POP on the left side of my chest... Needless to say, I wasn't able to push much with the left side today.

 

Anyway, on to the fitment of things.

 

 

Since this is a 6mt from a 2012 LGT, it has the alternate mounting system that you saw in previous pictures. I found out that I hadn't shaved of quite enough on my first try. I had to pull it out and grind it down a bit more.

 

 

Basically you have to get down to match the bellhousing dimensions to clear the turbo. Remember the 2012 LGT has that low center mount turbo, so the mount was here on that car. I also like this tranny dipstick a lot more than the 5mt. It's the little things some days.

 

 

To give you an idea of how tight a fit it is. I had to unbolt the turbo so I could get a little wiggle from it to get past when installing the tranny.

 

 

Trying to give you all an idea of how close you can get to the oil ports. Granted it's not much different than the 5mt, just showing that you can't cheat and leave too much of the mount behind.

 

 

Different angle, just shows how close the turbo is mounted to the bell housing. I've never pulled just the tranny with the turbo still on it before, so I hadn't noticed how tight the fit is.

 

 

What about the bracing fins for the 2010-2012 LGT 6mt? Good news is they clear everything. This is the driver's side, they sit under the starter and there is plenty of room there.

 

 

On the turbo side, they clear find because the turbo sits high enough and the downpipe narrows so it clears easily.

 

I was one inch from install last night, but had to pull it back down to grind down on the mount location on the passenger side before it would fit all the way on.

 

Spent about 2 hours this morning getting the angle just right to mate it up cleanly with the engine. It was a bear to do. I'm not sure whether I prefer to pull the engine or the tranny at this point, each has it's pros and cons.

[Infosecdad]

On to part two of today's work.

 

 

Knock off Bomba short shifter plate. Do not recommend. I like the idea, but this knock off must be just slightly off somewhere. First test drive it locked up on the gear selector and popped off the main cable from the shifter. Thankfully I ended up in 1st gear three blocks from the house so I was able to limp home with a disconnected shifter.

 

 

It's a really tight fit there. I have a Perrin shifter plate as well, I just had read that it was a little notchy because it doesn't have the counter weights. I decided to pull this one and try the perrin. I had disconnect the tranny cradle and use a big bar to move the tranny over enough to get this thing off. Perrin is installed now and the shifting is definitely better.

 

 

Love that I can keep my newer driveshaft and solid bushings for the driveshaft.

 

 

View from the back with it tucked up and set. Had to research the cable routing, it goes down the driver's side to a ring, then up and around the top of the tranny and one stays on top, the other goes down the passenger side (as seen a few pictures before).

 

 

The rear part of the tranny has bolt holes for exhaust down the passenger side instead of the driver's side, but it's set up just a little higher. After fitting my 3" down/mid-pipe on I found that I could drill a hole right inbetween the two stock holes and it lines up perfectly. Exhaust now actually fits a little better than before with the stock 5mt. Once the driveshaft is installed the cover can be removed, but it's just barely able to do so.

 

I have to wait until tomorrow for driving impressions. I don't have any other drivers at the house this evening to come get me incase I pop a cable for some reason. I'll test drive a bit tomorrow to build trust in it, then hope to drive it to my Vanderbilt appt on Monday.

 

I found that adjusting the main cable can make a big difference in feel of the shifter. Made a few adjustments to find the best shifting feel so far.

[Scottydunno]

I had the same issue with lining up the transmission with the turbo in place. I ended doing a swing and push movement to get it in place.

 

Where did the cable pop off? Under the shifter like what happened to me or down on the transmission? The adjustment is so that the shifter is centered in the 3-4 gate. I starting to wish I uploaded the rest of the pictures I took for a bit more clarity. I'll get to it eventually.. lol

 

As far as doing this on your own, why not? It really is this simple and straightforward.

 

Sent from my SM-G996U using Tapatalk

[Infosecdad]

I had the same issue with lining up the transmission with the turbo in place. I ended doing a swing and push movement to get it in place.

 

Where did the cable pop off? Under the shifter like what happened to me or down on the transmission? The adjustment is so that the shifter is centered in the 3-4 gate. I starting to wish I uploaded the rest of the pictures I took for a bit more clarity. I'll get to it eventually.. lol

 

As far as doing this on your own, why not? It really is this simple and straightforward.

 

Sent from my SM-G996U using Tapatalk

 

The cable popped off at the shifter, but it wasn't the side cable that popped off on yours, it was the main cable. Without it there is no gear selection at all, I was just fortunate that it dropped into 1st when it popped off.

[Scottydunno]

The cable popped off at the shifter, but it wasn't the side cable that popped off on yours, it was the main cable. Without it there is no gear selection at all, I was just fortunate that it dropped into 1st when it popped off.

That's odd. That cable has a built metal retaining clip. Must've been a real good jam if that popped off.

 

How was that short shifter.. well before the oppsie happened...

 

Sent from my SM-G996U using Tapatalk

[Infosecdad]

Yeah, it jammed up hard.

 

Had a short 10 min drive today, took her on I-40 for a few miles and around to get donuts for the kids.

 

60mph at 2200 RPM and 75 mph at 2800 RPM is heavenly...

 

The short shifter feels almost too short. 2-4-6 is all good with a solid thunk, 1-3-5 are all lighter/shorter and I'm not sure I'm in gear, but I am. Will see if it's something I need to adjust or just get used to.

 

The cabin noise is reduced, the 5mt OBXT tranny was really noisy by comparison. I'm sure the direct linkage with solid bushings probably contributed to all that noise. The 6mt w/ cables is silent, I don't get any tranny whine/noise; just more of the sweet turbo whooshes and titanium exhaust sounds.

 

I keep shifting into 6th trying to get to reverse, need some time to train the muscle memory to lift and shift. It's also going to take a bit to remember I have a 6th gear :-P I find myself stopping at 5th most times.

 

Tomorrow I have a 300 mile round trip so I'll get to see what impact it has on MPG and HWY noise over distance.

 

I'm excited, this is something I had dreamt of doing for almost 20 years now...

[Max Capacity]

Glad to hear you're up and running. Good luck on the drive tomorrow.

 

I quiet tranny in one of these wagons...I have the same dream... LOL

[xt2005bonbon]

Why didn't you keep the obxt rear diff? Didn't you say it would have dropped the rpm even more?

 

Oh and good job!

[Infosecdad]

Why didn't you keep the obxt rear diff? Didn't you say it would have dropped the rpm even more?

 

Oh and good job!

 

The OBXT rear diff is 4.44, the LGT 2010-12 6mt is 4.11 as is the WRX 2015+ 6mt (like the LGT 5mt).

I probably didn't write it up as well as I should have before.

 

I get to see more difference as not only am I getting a 6th gear, but I step down from 4.44 to 4.11. I had gone up to use a 5mt with half the miles as my original one.

 

So now at 75-77 mph I drop ~700 rpm with the 6mt 4.11 vs the 5m 4.44; it's fairly dramatic.

 

I'm also pleased that I can go to a current year 6mt if I want to, I went from a 16yo tranny to a 10yo tranny, and it's all setup to go to 2022 if I wanted to pay for it.

 

Thanks!

[Scottydunno]

Yeah, it jammed up hard.

 

Had a short 10 min drive today, took her on I-40 for a few miles and around to get donuts for the kids.

 

60mph at 2200 RPM and 75 mph at 2800 RPM is heavenly...

 

The short shifter feels almost too short. 2-4-6 is all good with a solid thunk, 1-3-5 are all lighter/shorter and I'm not sure I'm in gear, but I am. Will see if it's something I need to adjust or just get used to.

 

The cabin noise is reduced, the 5mt OBXT tranny was really noisy by comparison. I'm sure the direct linkage with solid bushings probably contributed to all that noise. The 6mt w/ cables is silent, I don't get any tranny whine/noise; just more of the sweet turbo whooshes and titanium exhaust sounds.

 

I keep shifting into 6th trying to get to reverse, need some time to train the muscle memory to lift and shift. It's also going to take a bit to remember I have a 6th gear :-P I find myself stopping at 5th most times.

 

Tomorrow I have a 300 mile round trip so I'll get to see what impact it has on MPG and HWY noise over distance.

 

I'm excited, this is something I had dreamt of doing for almost 20 years now...

Now that you mention it, I definitely don't hear any transmission/gearbox noise in the cabin at all. I guess I was just completely used to it that it just didn't phase me!

 

The 5th gear thing is real!! LOL, it took me a few trips to realize what was going on, especially with the RPM's being somewhat higher in 5th. My only real complaint is reverse. I wish it was designed like the GM T56. In that trans, reverse is one step to the left of 1st, so ideally in a parking lot, you can go from 1st to reverse very quickly and easily.

 

I'm glad your swap went well, enjoy the cruise!!

 

Sent from my SM-G996U using Tapatalk

[xt2005bonbon]

The OBXT rear diff is 4.44, the LGT 2010-12 6mt is 4.11 as is the WRX 2015+ 6mt (like the LGT 5mt).

I probably didn't write it up as well as I should have before.

 

I get to see more difference as not only am I getting a 6th gear, but I step down from 4.44 to 4.11. I had gone up to use a 5mt with half the miles as my original one.

 

So now at 75-77 mph I drop ~700 rpm with the 6mt 4.11 vs the 5m 4.44; it's fairly dramatic.

 

 

I guess even after all the stuff I have done to these cars, I am still a noob in terms of understanding gear ratio

 

 

So while keeping everything else constant, a lower gear ratio at your rear diff translates into a lower rpm in 6th gear, correct?

 

 

If yes, then if I do this swap on an OBXT while keeping the rear diff, my rpm drop would not be as dramatic as yours. I guess, the next question would also be, can you even install this trans to an OBXT while retaining the rear diff, or does this tranny require a 4.11 rear diff? Such a noob I know

[whitexc]

Rear diff has to match the trans/front diff.

 

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Edited March 7, 2022 by whitexc

[xt2005bonbon]

This explains why the OP had to change his rear diff then.

[BoozeRS05]

Yep, if I understand correctly the transmission final drive has to match the rear diff. The LGT shares the same FD as the newer WRX 6mt so our rear diff isn't a problem, unlike the OBXT.

[Infosecdad]

I guess even after all the stuff I have done to these cars, I am still a noob in terms of understanding gear ratio

 

 

So while keeping everything else constant, a lower gear ratio at your rear diff translates into a lower rpm in 6th gear, correct?

 

 

If yes, then if I do this swap on an OBXT while keeping the rear diff, my rpm drop would not be as dramatic as yours. I guess, the next question would also be, can you even install this trans to an OBXT while retaining the rear diff, or does this tranny require a 4.11 rear diff? Such a noob I know

 

Yes, the rear diff ratio has to match the tranny ratio or it get really unhappy trying to turn two sets of wheels at different speeds.

 

The 2010-2012 LGT and the 2015+ WRX 6mt are 4.10 ratios, so they match up well with 4th Gen LGTs as the diff can be reused.

 

The 2010-2012 Outbacks also had a 6mt, but theirs was matched to a 4.44 rear diff. So if you want to keep your 4.44, you could look for one of those trannys. You wouldn't get quite as much RPM drop as you would moving to a 4.11, but your OBXT also has bigger tires, so it might be worth keeping it at 4.44.

[Infosecdad]

Back home after my 300 mile round trip to Vanderbilt.

 

I love it :wub:

 

Cruising down the interstate at 2900 rpm at 78 mph is amazing.

Big smile every time I can shift into 6th gear.

First 300 miles resulted in an estimated 3-4 mpg improvement on the hwy.

 

No tranny noise and 600-700 less rpm makes it a good bit quieter.

I guess I was used to how much noise came from the 5mt, granted I had a bunch of hardened or solid bushings in there for shifting feel.

 

The cable shifter needs just a little adjusting I think for 1-3-5 feel, but 95% of the time it's solid. There is basically no play in it right now; firmer than I ever got the 5mt with solid bushings. I'm double checking if it's really in neutral because there is no play at all. Shifts are nice, short, and clean. Getting used to 5 and 6 because they aren't as far to the right as my mind thinks they would be.

 

I'll post a final tally of what I picked up for parts and such if someone comes along later and wants to do something similar.

[Scottydunno]

Back home after my 300 mile round trip to Vanderbilt.

 

I love it :wub:

 

Cruising down the interstate at 2900 rpm at 78 mph is amazing.

Big smile every time I can shift into 6th gear.

First 300 miles resulted in an estimated 3-4 mpg improvement on the hwy.

 

No tranny noise and 600-700 less rpm makes it a good bit quieter.

I guess I was used to how much noise came from the 5mt, granted I had a bunch of hardened or solid bushings in there for shifting feel.

 

The cable shifter needs just a little adjusting I think for 1-3-5 feel, but 95% of the time it's solid. There is basically no play in it right now; firmer than I ever got the 5mt with solid bushings. I'm double checking if it's really in neutral because there is no play at all. Shifts are nice, short, and clean. Getting used to 5 and 6 because they aren't as far to the right as my mind thinks they would be.

 

I'll post a final tally of what I picked up for parts and such if someone comes along later and wants to do something similar.

Stock setup, 5th and 6th feels close to 3rd and 4th as well. I'm elated that it's not just me.. lol

 

What did you average for MPG??

 

Sent from my SM-G996U using Tapatalk

[xt2005bonbon]

Yes, the rear diff ratio has to match the tranny ratio or it get really unhappy trying to turn two sets of wheels at different speeds.

 

 

So this implies that someone with an OBXT cannot just swap a trans from an LGT unless they swap the front diff too, or keep the front diff from the lgt but then swap the rear diff. Fun stuff!

[Infosecdad]

Stock setup, 5th and 6th feels close to 3rd and 4th as well. I'm elated that it's not just me.. lol

 

What did you average for MPG??

 

Sent from my SM-G996U using Tapatalk

 

I used to get around 22 mpg for high 70's, today was approx 26 mpg for high 70's

[Infosecdad]

So this implies that someone with an OBXT cannot just swap a trans from an LGT unless they swap the front diff too, or keep the front diff from the lgt but then swap the rear diff. Fun stuff!

 

I haven't seen someone pull a front diff as it's part of the tranny, but I guess it could be done.

 

Basically, if an OBXT wanted to do it you either need the tranny and matching rear diff (4.11 is pretty common so should be easier to get) or find one from the 2010-2012 Outback that is setup for the 4.44 diff.

[xt2005bonbon]

Right. I remember starring at that front diff 5 years ago when I took my trans apart. I had to change the center diff which partially exploded. Sent a few pieces here and there in the trans.

 

 

 

Well, good job man. Perfect timing in terms of increase mpg when gas price jumped 70+ cents in a week .

[Infosecdad]

Update after a week.

 

100% love it and would do it again in a heartbeat.

 

I understand that's it's not for everyone, it's a split case 6mt with cable shifter. If you are going for 400hp+ and/or prefer the direct linkage for the shifter, then go for the STi 6mt.

 

However, if you are <400HP (honestly, it's the torque and how you drive it that matter more, people just have a tendency to measure by HP) and don't mind the cable shifting, then this is a perfectly viable option for 1/2-1/3 the cost.

 

You can use a 2010-2012 Legacy/Outback 6mt (with some minor mods) or a 2015-2022 WRX 6mt. All you need is the transmission and cable shifter mechanism, and to make sure your rear diff matches. Most of the split case 6mts are 4.11, but there are a few 4.44 from the Outbacks.

 

The list of things I could reuse from my 5mt setup:

- Driveshaft

- Transmission cradle w/ bushings

- CV axles

- Flywheel and Clutch

- TSK Throwout Bearing

- Verus Harden fork and pivot

 

The 2015-2022 WRX 6mt is the easiest because it's the same mounting system as the 5mt in the 4th Gens. Plus, it's newer, but generally a little more expensive than the 2010-2012 Legacy/Outback 6mt. It looks like the cable shifter mechanism can be interchanged, I'm using a 2020 WRX shifter on the 2012 LGT 6mt and it works great.

 

Due to the unique mounting system for the 2010-2012 LGT there are a few extra things you have to do to get those 6mts to fit. You need the dogbone mount off your 5mt because it doesn't have one and you need to cut/grind off the mount on the passenger side (as documented earlier in this thread) so that it can clear the turbo. Other than that, the rest of the case differences don't really matter. I'm going to claim than the extra bracing in the case due to the mounting system provides a stronger case (but I honestly have no idea ). I did pull over the two sensors from my 5mt as well, they just plug in at the same locations.

 

I love that I can now upgrade to a 17 year newer transmission in my 2005. One day I may bump from my 2012 6mt to a 202x 6mt if I need to. The 6mt is definitely quieter and smoother shifting than my 5mt, and it has more miles on it. Road noise is down due to the cable shifter isolating sound better and lower RPM from the 6th gear. So far MPG is up 3-4 mpg in hwy driving.

 

I highly recommend the upgrades that the WRX crew has known about since 2015, the short shifter, the short shift adapter plate, and the shift stop. Right now my shifts are very tight and smooth. It's honestly tighter than my 5mt ever was even with solid bushings.

 

I did pick up a seal kit for the 6mt because I wanted to replace axle and rear seals before install. I also picked up the washer and cotter pin and four bolts for attaching the shifter mechanism to the body.

 

It amazes me that 16 years later, I can bolt the cable shifter mechanism to the exact spot with the same four bolt holes as the surround from my 5mt, I love Subaru engineering.

 

When I get a chance, I'll post about my attempts to get the Moore v2 blast plates to work. I may try again someday, but I ran out of time and couldn't afford to have any setbacks at this point.

[rhino6303]

I just mocked up my shifter assembly. I have the kartboy short shifter setup with oem linkage assembly. Even without the shift stop and not being mounted in the vehicle this feels better than my 5MT setup ever has (with TIC bushings everywhere). The shifts are crisp and knotchy. I'm going to wait on a shorter lever and different knob until later.

[Guest]

Kudos for an original project.

 

Having 6 forward gears is nice. But the cable shifter would be a deal breaker for me, I think. One of the nicest traits of old school manual Subarus is the direct shifter linkage, especially when mated to STI 6MT. But, obviously it comes at a cost.

 

Also sorry to hear about your Covid woes. Covid sucks.

[TMBLKDG]

Wow, great read. I need to go off and read Scottydunno's thread now.

Given that I was considering sending my 5MT off and having it all redone by ZF Design, this thread has probably saved me from that.  By the time I had them do everything to it and got some blast plates for it I'd be looking at close to $5K.  If I can pick up a newer WRX trans for half that (or less) and just bolt it in with a little work for the shifter, that sounds like a WAY better deal.  Plenty strong for my mod level, quieter, and better freeway MPG (I commute about 70 miles/day on the freeway), it's a win-win-win.

The only downside is that I have a nice Latheworks shift ball that I really like for the 5MT that won't fit the 6MT shifter.  I'll have to look at what the difference is, maybe the hole can be drilled oversized or an adapter can be made.

Thanks for the great thread Infosecdad!