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The Great Transmission Swap

Parts needed:

Transmission
Clutch
Flywheel
Pressure plate
Pilot Bearing
Throw-out Bearing
Driveshaft
Shifter assembly
Pedal assembly, (brake & clutch)
Clutch master and slave cylinder
Hydraulic clutch line
Starter Motor
3-piece rear crossmember
Recommended: engine and transmission mounts


Day 1, Thursday, February 14th.

I took half of the day off to get to SLC and get started. This day was one Id been looking forward to for some time; I was excited to get the project going.

I arrived close to 1PM, and we pulled the car in shortly thereafter. We looked over the parts again, still not sure if we had everything we needed. Parts I knew wed need included a clutch hose that went from the master to slave cylinder. This was supposedly coming, but hadnt yet. Id received some crossmembers that werent originally sent on the day before, so we went to work.

Charlie began disassembling stuff on the topside, removing the top engine pivot mount and a few other items. This is when I finally decided that I needed to make sure the clutch hose was coming. I called and was informed that the hose wasnt in stock and was on national back order, oops. I was a bit disappointed, and Charlie was hesitant to start into the project while missing such a crucial part. Unfortunately it would not be the last important part to be missing.

Since Charlie also had some other work to do, he decided that the best thing to do would be to hold off on the project till the next day. In the meantime, I went around to a few places, looking for anything that would fit the line. It turns out that its basically a brake line, but shorter. Both ends are exactly like those youll find on a standard brake line, with a banjo fitting on one end, and female threaded screw-down type on the other. Salvage yards wouldnt sell me hydraulic lines, but an extremely helpful gentleman at the Murray Pep Boys let us dig through his inventory, where we found a number of candidates. I purchased a Raybestos line, content that it would do the job.

Meanwhile, a later model clutch line was being sent to me by mail, hopefully arriving the next day.

Day 2, Friday February 15th

6am was the agreed upon time for starting the work, though Charlie had been there at least an hour earlier. Hed removed the mount, turbo chimney and lower arm bar. Also disconnected were the lower ball joints, so that the axles could be pulled outward and away from the splines on the transmission. At this point we discovered that the inner CV boot on the right front side was recently torn. A replacement Subaru boot was ordered and delivered.

Next to come out was the downpipe. Five bolts up on the turbo, two on the transmission and another two on the flexible joint. There was another mount, but it had broken off at some earlier date and was rattling around, trapped by the shielding. The mount was re-welded in place. At this point it became obvious how pathetic the stock downpipe really is. Its at least 2”, but it allows for no smoothness from the wastegate and makes a terrible angle when it turns toward the back of the car. A much smoother, larger replacement would be much better suited, while replacement of the catalytic converter itself should yield some benefits when placed later in the system and replaced with a higher flow version.

The driveline was removed as a whole. The rear portion can be re-used, as the front is simply a bit longer for the manual version. We eventually replaced the whole unit, as theyre usually balanced on assembly, and it just seemed like the sensible thing to do at the time.

Now with everything disconnected from the transmission, it was time for it to be removed. A transmission jack was employed to keep it steady, while strapped down. The rear crossmember was unbolted and the four mounting bolts holding the transmission were removed. Also at this time, the four bolts holding the Torque Converter to the flex plate were removed through the hole previously occupied by the starter motor. The transmission will not likely come off without removing these.

At this point I was getting really excited, there was no turning back now. With the transmission out, we could actually see how much larger and heavier it was than the 5MT that would replace it. Its much wider on the bottom, longer, and generally bigger in every way than the 5MT. Given the amount of fluid it uses throughout the system, the weight savings were really starting to add up. How much would the removal of weight over the front axle improve performance and handling? These were the kinds of things running through my head.

Part of the process of actually removing the transmission involved a device that ran front one side of the engine bay to the other and had a J-hook running down from it. This hook went through an eyehole right next to the alternator. The bolt was then cranked up, pulling the front of the engine upwards and allowing the transmission to be removed easily. This is necessary for both removal and installation of the transmission. Ive heard of shops using a 2x4 to accomplish the same thing. While not nearly as elegant, it seems to do the job well.

Charlie suggested that I get to work removing and installing the pedals while he replaced the CV boot on a Saab 9000. Pleased that I could at least get my hands a bit dirty on this job, I went at it. Removing the stock brake assembly isnt hard, but it sure isnt easy. Six bolts hold the pedal in, as well as the clevis pin for the master cylinder. Five of the bolts are relatively easy to get to, after removing the cover underneath the steering wheel. The sixth bolt is decidedly difficult to get at, since the brake pedal and the steering column limit access to it. A little bit of tweaking by Charlie eventually got it out.

Installing the new pedal assembly included one of those moments when you think “nobody said anything about this!” I removed the shift lock/buzzer box that was right behind the steering column and the TCU in an attempt to get the pedal assembly to go in. I quickly ran up against a problem. The master cylinder piston goes through an O-shaped hole in the assembly. This hole is plenty big, but its also solidly an O. There was no way to realistically push in the piston, so we came to the conclusion that removing the Master Cylinder and vacuum assist was the only way to get it in. Removing these and pulling them toward the front of the car did the trick, but I also had to remove the left side of my strut tower brace and relocate my DIS-2. It also meant bleeding the brakes, ugh.

Installing the pedals also involved removing the gas pedal, and more work for Charlie trying to get wiring harnesses out of the way. Once the pedals were in, the same bolts were used to mount the assembly, though an additional one was needed above the gas pedal.

The shifter assembly was relatively easy to remove. Two screws in the elbow storage box and two all the way in the front were all that we could see at first, but the center section revealed no more. It turns out that this section needs a bit of prodding to pop out, where two additional screws are located, almost in the center. Be careful when removing the center part, the plastic can be marred easily if forced too hard. Removal of the shifter itself was just six screws and a nut or two underneath on the transmission. There are also three sets of wires leading off to the right side. One is power, one is a park position sensor, and Im thinking the third is a reverse indicator, though it could also be the “manual” mode lead. Alex has more information on these; Ill update it when I find out what everything is.

In order to get the shifter out in one piece, removing the ABS box right in front of it is necessary. There are four torx-type bolts holding it down, but unfortunately the left front bolt is concealed under the wiring harness to the ABS unit. This harness is a little tricky to get off. An alternative would be to remove the bolt holding the assembly together in the rear, right under the shifter. This would probably break the unit into two parts and make the ABS box removal unnecessary. Either way, it comes out.

Installing the new shifter does involve some work under the car. At the rear of the shifter is a bracket that attaches to the body, right behind the shifter in the tunnel. Charlie had me hold the shifter assembly in place while he lifter the car and installed the bolts into the holes. Thank goodness all of the holes are there for both MT and AT versions! The same six screws are used to cinch the assembly to the center console. In reassembly, I realized that the MT and AT center section were indeed different. The AT is much more elongated and the boot wouldnt fit. Im going to have to find a black MT center section now; in the meantime I get to see the whole assembly in its nakedness.

Finally we were ready to install the MT, but we quickly realized that we didnt have all of the crossmembers we needed. The transmission mount, while attached, was both in questionable condition, and only attached with one bolt. Having a Lowes home improvement center within walking distance again proved invaluable, but we were missing more than bolts.

The rear assembly is composed of three parts, two laterals and one longitudinal. In other words, its an H-shape, with the tranny mount attaching just forward of the center point on the crossing bar. The problem was that we were entirely missing the rear section. This wasnt good, not at all, because while the transmission could be installed without it, it would surely be able to shake even more. This was another one of those moments that we dread. I called and explained to John that we were missing some more pieces, but I was in a bit of a panic because it was Friday. While Saturday Delivery was an option, it wasnt likely to go very smoothly due to the Olympics in town and enhanced security. What to do?

Thankfully, Charlies shop is in the midst of a large “alley” of car repair shops, which included a salvage yard. We hurried down to the yard and were relieved to find that they indeed had a replacement crossmember assembly. It seems that all Legacy and Imprezas use the same crossmember, since the transmission is the same as well. $20 later, and smiling with relief, we returned to the shop and dropped off the parts. It was well into the afternoon, and Charlie had been working for the whole day.

Saturday, February 16th.

We began what we hoped was the final leg of the process at about 9AM. With the proper parts to mount the transmission, we began the process of installing the flywheel and clutch assembly.

Early in my swap planning, Id neglected to realize how important a new clutch was in the grand scheme of things. I'd figured that I could use the used clutch and flywheel for a while, and then simply replace them with aftermarket upgraded parts later. After some research into the subject, it quickly became obvious that I should really do it all while the opportunity presented itself. Pay for the parts now and get the install over, or pat $300-500 for install later. Thankfully fundage was available to get the necessary parts.

On the flywheel side, it's common knowledge that a lightened flywheel is a good thing in 9/10 cases. The stock flywheel weighs anywhere from 22-26lbs, while most light versions are 8-14lbs. There are both lightened stock units, aluminum and chrome-moly units available from any number of sources. Lightened flywheels are not a great idea, so the general consensus goes, because removing a sizeable amount of material from such a precision part can occasionally expose defects and problems in the original metal. That was quickly dismissed as an option.

Aluminum is definitely a light metal, and some companies use it for flywheels. The problem with bare aluminum is that it wears like nobody's business. The only realistic application of a bare aluminum flywheel would be in a situation where the transmission would be removed frequently. Other companies offer aluminum versions with replaceable facing made of a more resilient material. This is a reasonable option, but still not the best.

I eventually decided on a Chrome-Moly alloy version from one of a host of manufacturers. I was impressed by the JUN, Exedy and Fidanza parts available. Fate stepped in, however, and an I-club member in Florida by the name of Sunrise City Rider happened to have a brand new Exedy flywheel meant for a WRX that he was desperate to relieve himself of. The price was right, significantly less than the price advertised elsewhere on a multitude of sites. In a few days, my new Exedy flywheel was in my hands. This is light? I guess so!

Brennan of SubySports was kind enough to inform me that the WRX and Legacy share the same flywheel bolt pattern, while the Impreza apparently uses a different one. Keep this well in mind when purchasing a replacement flywheel.

On the clutch front, things were more complex. So many companies had so many products to offer, but which one was a good compromise for drivability, wear and power handling. In the early rush of turbocharged 2.5Rses, ACT was a popular clutch to use as a replacement for the stock unit. Time passed, and many trannies later; ACT is regarded frequently as a transmission killer. Clutchmasters' Stage one and Stage three were also put forward as very good options with respect to my needs. Several other brands were also considered, but I decided against all of these.

The Legacy turbo transmission was unique in the US until the introduction of the WRX. It was basically the transmission from the overseas Legacy RS. Instead of the clutch fork pushing forward, the turbo version pulled away from the flywheel to disengage the clutch. It was also the only version to use a hydraulic system instead of cable operation. This meant that the pressure plate was completely different. Remarkably, the introduction of the WRX probably made the availability of aftermarket clutches for the Turbo much more prevalent, as they use the same exact system.

While ranting on the LegacyWorks forum about deciding what clutch to get, Jason Grahn suggested I call Richard Buckner to see what he recommended. Richard works for Royal Subaru in Oregon and has an incredible amount of hands-on experience with the budding SCCA ProRally scene as well as the other US and Canadian programs. This presents him with unique insight into what works and what doesn't under stress. I called and talked to Richard and he informed me that Paul Eklund of Primitive Racing had previously had problems with the ACT clutch in his EJ22T equipped rally Impreza. Richard recommended the non-US WRX pressure plate and it's still running on the car, almost two years later. I was sold. Richard also recommended the Group N clutch disc as a good upgrade from the standard version, without getting a hard feeling take-up. A new Pilot and Throw-out bearing were also ordered.

Installing the Flywheel was a cinch. Since it's balanced from the factory, it's not necessary to line it up in any particular way, so the eight bolts were installed, along with the pilot bearing. The clutch was put in place with the aligning tool, while the pressure plate and TOB were assembled. Keep in mind that the TOB needs to be installed on the pressure plate before it's installed onto the flywheel. The “pull” nature of the assembly means that the TOB is pulled towards the rear of the car and needs to hook around the center of the pressure plate.

With these part installed, the transmission was prepared for installation. Two dowels were installed into the engine to help align the bolts. With the crossmembers installed, the MT was placed onto the transmission jack and strapped down. The engine was also re-tilted in order to facilitate the install.

Before installing the transmission, however, the clutch fork has to be detached so it can be fitted over the TOB. There's a hex-head plug on the left side that needs to be removed, then the pivot shaft can be removed and the fork pulled upwards. Once the transmission is installed, the fork is maneuvered into position from above and re-secured.

Installation is pretty straightforward; just move the tranny forward till it engages into the clutch and mates solidly with the engine. Backing off or removing the engine hoist will help the crossmember install, and the transmission is not going anywhere if it's securely attached to the engine.

Again, while the rear portion of the driveline is identical to the AT model, we decided to replace the entire assembly rather early on, so we went about preparing it and installing. There's a single crossmember next to the yolk and simple bolt/nut attachments at all three connections. Simple work.

Before reinstalling the halfshafts, the torn CV boot had to be replaced. This involved removing it entirely, so the wheel came off, and the nut on the spindle was removed. The shaft came out pretty easily, it's amazing how simply this work is done with the right tools, and pneumatic ones at that. The clips were removed from the old boot and the bearing assembly was removed. Since the bearings still had a good amount of grease, we were confident that the unit was still at least in good shape, without inspecting it too closely.

Instead of using light grease, Charlie informed me that the later Legacies had a problem with the grease being too thin and leaking out of the bearings. Instead, he used heavier, reddish grease, packing it into the bearing cover. He then forced the cover over the bearings while they were on the shaft. This had the effect of pushing a great deal of the old, dirty grease out from the bearings. Cool.

With that task completed, the reinstallation of the shafts was continued. This area is where one can cause problems by installing the pins incorrectly. There is only one “right” way to install the pins, and if done improperly, the pins will go in, but might never come out. Charlie used a tool with a cylindrical shaft to make sure that the shaft and splines were indeed aligned properly and installed the pins.

After the halfshaft install, the ball joints were reinstalled and all bolts, connections and fittings were re-checked. Finally, the downpipe was reinstalled onto the turbo and exhaust. Unfortunately, the brackets on the downpipe were meant to attach to those on the AT, whereas the MT has different attachment points. Since we had limited facilities, and the welding shop was closed, we simply made sure the pipe was as secure as it could be made at the moment. The lower arm bar was reinstalled and again, everything was checked over.

One of our concerns was whether the speedometer cable would reach, since the AT's attachment point was much closer to the front left side of the transmission than that of the MT. Thankfully, the cable had no problems reaching. It does take a little tinkering to get to fit well over the tube, however, as the first time we drove it, it wasn't working at all.

At this point, Charlie installed the clutch fork and began to connect the clutch hydraulic cable. The Master cylinder soon went in and everything was cinched down. The brake master cylinder was then reinstalled and attached to the pedals. The ignition was put back in place, the strut tower bar reinstalled, the rear pivot mount was installed and the intake replaced. The chimney was also put on with some new bolts, as most of the old ones were very rusted. Also remember to reconnect the throttle cable if you disconnected it when removing and installing the pedal assembly.

Another one of those moments occurred at this time. I'd taken a walk to the friendly Lowe's hardware store again, to get those replacement bolt for the turbo chimney, when a couple of friends came in and told me that the starter motor was different. Oh great. Here I was in the waning part of the project and something like this had to happen. In the back of my mind, I considered the possibility that I would need a different one, but never dwelled on it long enough to check it out. We took off towards the salvage yard, only to find that they were closed on Saturday. Well, they had to take off, so I was dropped back at Charlie's shop, with a genuinely daunting problem to overcome.

Calls were made to several dealerships; rebuild shops and parts stores, with displeasing results. It seems that the MT model was almost completely unavailable in the state. I was quoted anywhere from $109 with core to $225 without, and everywhere in between. Tired and mildly depressed at this point, I decided that my only option was to drive to the local “pick-n-pull” and see if they had a Legacy or Impreza. The problem was, would they have, either in an MT, and if so, would the engine or starter still be present?

Needing a starter, I got a few tools and took off in the MT Astrovan, determined somewhat to get a starter. I wasn't too confident that they'd have one, based on my luck during the project. After paying my $2 to get in, I proceeded to the “misc Jap” section and searched for some newer Subarus among the earlier models, Mitsubishis and Mazdas. It's telling when Hyundai's section is larger than “misc Jap” in its entirely. Car after car I searched, finding one after another Legacy, but all automatic. It was looking bad, but off in the distance was a beige wagon that held my last hope. Sure enough, it was an MT. Incredibly, it had both the engine and starter, so I got right to work. First I detached the electrical connectors and got a 14mm socket to remove the top bolt. It was tight, but came out pretty easily. This bolt is needed with the starter itself, because it's a different length than the AT version, I think.

The bottom nut, however, would prove a daunting task indeed. It's on the bottom, but about 8 inches from the back of the starter itself. I had an extension that was a perfect length, but no matter how hard I cranked, it wouldn't budge, It even felt as if it were rounding the nut a few times, the worst thing that could have happened. The socket I was using was not a new one. Its edges were slightly rounded and not holding very secure. Not only was I using a bad socket, but also an 8” extension and ratchet made for a wobbly fit. It was also in the mid-30s, beginning to get overcast and with a slight wind. I even tried maneuvering the ratchet so I could attach the socket directly to it. While this worked, even putting my entire weight on the ratchet proved ineffective. I was cold, pissed off and tired.

Back at Charlie's I grabbed a short length of pipe and a 24” breaker bar, resigned to the fact that if these tools didn't get the job dine, nothing short of removing the engine would get it out. After attaching the extension and same socket to the bar, I tested the fit. It felt much better than the ratchet because it had less slack. Confident in the fit, I began to pull the bar, putting increasingly more pressure on it until I was closing in on my limit. POP!

Success. The nut had relented to one of the most basic mechanical principals. $25 later, I was headed back with a grin on my face. I'd saved a bunch of cash and we could finish the project.

The starter installed and worked just fine, but we ran into a problem when bleeding the clutch system. For some reason the pedal wouldn't disengage the clutch fully or come all the way back up. Charlie was convinced that the master cylinder was at fault, and that a new one was needed. My elation at conquering the starter was dashed as I realized that the master cylinder would cost at least as much as the starter motor, and probably be harder to get.

On this sad note, I found a ride to take me back home, 40 miles north, and left Charlie to think about the problem and resume work on Monday.

Monday, February 18th.

This particular Monday is the US Presidents Day, and I had the day off. Thankfully I didn't need to find a ride to and from work, but home offered very little to distract me from the state of the project. I called Charlie at 9AM and was delighted to find out that he'd resolved the clutch problem with a simple adjustment of the master cylinder piston. The clutch was working perfectly, thought the key was stuck in the ignition. The ignition switch is different on the AT, to prevent the removal of the key unless the shifter is in park. I was again elated, and agreed to call him back in a few hours to check on the progress. At about 1PM, I called and Charlie told me to come on down, that the car was ready to go.

As I arrived, he was just headed out to take it for a drive, but jumped out and told me to take it for a spin. I immediately jumped in and made myself familiar with the feel of the clutch and shifter. The clutch was just about perfect. They hydraulics were taking up just enough of the effort to make the engagement very smooth but prompt. The shifter was a little messier. One missing item was the spring that re-centers the shifter, so presently it tended to flop around a bit. I shifted into a few gears back and forth to feel the action, and then took off.

Immediately, the lightweight flywheel made its presence known. I didn't kill the engine, but it did require a few more revs to properly engage. Turning onto the street, I was immediately delighted by the linear power all the way up to at least 5000 rpm; shift to second, boost comes in quickly and into third. I immediately notice that the speedometer isn't working, but I'm certain that I'm well over 45MPH. Good grief.

Without my boost controller connected, and running about 6.5PSI of boost, I'm giggling to myself and I've just confirmed that the money and effort were all worth it. The car was easily as fast, if not faster, than with nearly twice the boost. Dawdling around the back streets in brief pulses of power, I quickly oriented myself with the transmission and clutch. I again noticed how perfectly the clutch engaged, how well it shifted gears, and how linear the power was at such low boost.

Later I realized that the DIS-2's main power had been disconnected, so reconnected it. The power again improved slightly and smoothed out more, just like it'd noticed after installing it. The speedometer simply needed to be re-seated and now works perfectly. The key lock was easily defeated by shorting two of the wires originally attached to the AT shifter to fool the car into thinking it was in neutral. This apparently disables Cruise Control, but Alex installed a relay that overcame this. I'll investigate further.

I still have to get the reverse lights to actuate properly, but it's just a matter of finding out which wires on the old harness were responsible for this, then wiring them up to the switch on the transmission.

I did not reinstall the TCU, and I'm not sure if that's going to cause problems or not. I do have a significantly higher idle than before, and it's slightly rougher aswell. Based on information I got from Al on LegacyWorks, there's a single wire on the ECU that tells it whether it should be and AT or MT ECU. I probably just need to make sure I have the right wire, this B48 #20, snip it, and see if that helps out.

A few other minor issues are the transmission filter and lines. The cooler is integrated into the A/C condenser, so removing it is a process in itself, but it would make excellent oil cooler, given the proper plumbing. This could be a potential upgrade for those with MT cars and no oil coolers. Swapping in the AT and A/C cooler from an automatic puts the cooler in a prime position and eliminates the hassle of installing a cooler elsewhere.

The center section of the console will need to be replaced if the stock boot and assembly is to look any good at all. Finding the right color might be the most daunting aspect of this task, as the early Legacies came in a lot of colors. My interior is black, not a very common color. I will also be adding a short shifter soon, with harder bushings. By all measurements, the RS shifter should fit perfectly, though I won't know until I try.

I will also replace the old transmission mount with at least a new stock version, if not the Sti hardened version in the near future. I'd like to do the same with the engine mounts, but that's a different thing entirely.

Well, that about wraps up the transmission swap. It's a job that a shade-tree mechanic could perform, given the proper tools and enough time. I was lucky enough to have an enthusiastic mechanic with experience to help me out. The result is a very satisfying car that is unique in many regards. Thanks to all those who helped me get this done!