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Old 12-25-2014, 09:35 PM   #1
GravelRash
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2002 WRX Franknwagen
Grime over Sedona Red

Default '02 WRX wagon auto to manual drive train swap...a cautionary tale

The elephant in the living room: WHY??
- Original '02 manual car was t-boned in the passenger door, e.g. totaled...but no drive train bits were damaged. I loved that car...sob
- I wanted to re-use my Prodrive PPP3, my 4-pot brakes, rear disks/pads...
- I bought the car back from the insurance company, and found a clean, one owner, '02, same color, decent price...but auto
- Couldn't wait around for another car, so I bought it
- I have the full factory shop manual set: an absolute prerequisite!

Eventually I got around to the swap. Everyone I knew in the community thought I was nuts, but gottas have that manual back.

I've been mucking about with mechanical stuff my entire life, and quite a bit with Subarus, so the mechanical stuff was straightforward, but rather laborious doing it all myself with limited garage space to work in. The fact that I was working with 2 cars of the same body / engine / year eliminated all the mechanical pitfalls discussed in countless other conversion threads. Piece of cake.

NOTE: I'm glossing over all the minor details here, like getting the front axles out of the trans, attaching the engine to the hoist, etc., etc., etc...

Also note, as mentioned in many other threads, the rear diff ratio is NOT the same between manual and auto: you MUST swap the diffs also.

There was no (practical / safe) way to get the car up in the air far enough to get the trans(s) out / in from under the car...so I pulled both engines w/ trans attached. Worked fine, just took it slow and carefully. Moveable engine hoist absolutely essential...

A handy trick to installing the engine w/ trans attached: fold up some sturdy corrugated cardboard to tuck between the trans and the firewall end of the trans tunnel. Worked like a charm, 'cause the unit has to go in at quite a steep angle to avoid body structure bits. Cardboard was slick enough it just bent to fit the body and the trans slid right down and back into place. Ymmv...

There are 2 ways to swap the rear diff: yank out just the diffs and swap them, or swap the entire rear subframe. Swapping just the diffs seems like the obvious answer...but you actually have to do more disassembly / reassembly that way. The entire rear subframe comes out with 4 bolts. No disconnecting suspension bits to get the axles out, no de-mounting the diff while getting fluid everywhere, etc. Plus I knew my rear brakes were in good shape and was going to keep them in either case.

Of course, the entire subframes aare a bit heavier than just the diffs, and need to be supported. I used a floor jack, both to support them under the car and move them around.

I elected to pull the emergency brake cables with the subframe. Disconnecting / reconnecting in the car is a giant pita, though, so I'd look at how difficult it would be to disconnect at the brakes.

Ok, the mechanical stuff's all done (!?). So, how 'bout that electrical?

The good news: the instrument pod is just a straight swap! And in many cases - but not all - you can tap into the circuits you need using the existing auto harness connectors. Once you've figured out the "details".
The bad news: that's all the good news there is.

I'm pretty good at electrical stuff, and I did get it figured out. Eventually. The factory electrical manual is absolutely essential - once you've figured out all the place where it does NOT show you the info you desperately need:
- There are some excellent pages that show the different wiring paths and components for manual vs. auto installs.
- There are many other pages that show only one or the other...and don't tell you which.
- Many of those other pages lead to wrong assumptions, subtle conflicts in the info, considerable creative use of language, and hair loss.
- The ECUs are identical - except they're wired differently in a couple of critical places.

After exhaustive analysis of the manual I did find ways to connect to the existing wiring harness for all but a couple of connections in the cockpit. So I only had to run 1 (2?) wires through the firewall.

Everything works, and Frankensubie is again a joy to drive!

The astute reader has probably noticed the lack of actual wiring details above. That's because I'm writing this on a whim, and I'm not where I have access to all my notes/diagrams/scribblings/ and the manual.

If anyone actually needs those details at this late date I can come up with the answers...

Caveats:
- Can you perform this swap between, say, an '02 and '03, or an '05 and a '12, or...?
- I don't have a ******* clue, and I wouldn't presume to guess.
- One would think that '02 - '05 swaps would be pretty straightforward, but...I won't even guess.
- Do not, under any circumstances, consider this swap in the opposite direction. Mechanically, no problem. Electrically...only the clinically diagnosed masochist should attempt it.

Hopefully this will be enlightening to the innocent, remotely helpful to anyone insane enough to attempt this, and roll on the floor to those who have been there...
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Old 12-26-2014, 04:16 PM   #2
hopperjon
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I was under the impression that swapping the main harness that runs underneath the dash would make this swap so no wires had to be tapped into... Maybe you didn't want to pull the dash? Or maybe my impressions are wrong
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Old 12-26-2014, 07:53 PM   #3
GravelRash
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Grime over Sedona Red

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You're probably not wrong, for the most part. You're definitely not wrong that I didn't want to pull the dash.

I didn't have to actually tap into the existing cockpit harness wires. I just used some generic spade connectors that I trimmed one leg off of, and the remaining leg plugged into the appropriate existing connector socket. Most of these plugged into the 5 connectors that used to plug into the auto trans controller module, conveniently located above the clutch pedal. Far, far, easier than pulling the dash and swapping the harnesses!

Note: for every item that was connected to a harness in the manual car I generally left the plug attached, and cut the wires as far back from the plug as was convenient/possible. So I had wiring to attach new connectors to, and/or extend to reach the necessary connection on the auto cockpit harness. (I also salvaged every other connector in sight, with as much wiring as was convenient, just for future reference. I have a milk carton crate full of that stuff...)

Example: the wires coming from the clutch pedal position switch(es?) can be either siamesed with the brake pedal switch(es?) connectors, or have a trimmed spade connector added and plug into one of the aforementioned trans controller sockets.

Even if you do pull the entire dash, the main cockpit harness wraps over-under-around-and-through so many openings and structural bits that it would help to be a snake charmer. And the harness is securely taped to something just about everywhere you can't reach. Plus it has a bazillion other connections that have nothing to do with the swap. And you'd have to unplug every one of them, and then get them all plugged back into the new harness. Add different connector colors and configurations, and mounting locations/orientations, and I don't know if it would all actually be plug-n-play...

And that still leaves you with the one connection from the engine compartment to the ecu: the manual trans speed sensor. There's no workable connection from the sensor to the existing engine compartment harness, and no access to that circuit in the cockpit. And really, pulling one wire into the cockpit isn't a big deal, just a pita to route it neatly all the way over to the ecu.

I'd love to swap stories with someone who actually did the cockpit harness swap. Assuming, that is, that they're not locked away somewhere under heavy sedation...

Quote:
Originally Posted by hopperjon View Post
I was under the impression that swapping the main harness that runs underneath the dash would make this swap so no wires had to be tapped into... Maybe you didn't want to pull the dash? Or maybe my impressions are wrong
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Old 12-26-2014, 08:11 PM   #4
GravelRash
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2002 WRX Franknwagen
Grime over Sedona Red

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One other little quirk that you won't find in the manual. If you leave the key in the ignition of the auto car when you pull the battery...you can't get the key out of the ignition switch. Ever.

Or, if you did remove the key, once you've done the swap and you insert the key and fire it up, and everything works just like it should, when you shut off the ignition...you can't get the key out. Ever.

Unless, that is, you find the appropriate connector that came off the auto shift lever module and permanently jumper the 2 connections in the plug. That bit was connected to the switch for the Park position of the auto shift lever...which controlled the locking mechanism in the steering column that prevented you from removing the key unless it was in park. No "Park" position, no remove key...

Or, of course, you could just swap the entire steering column over from the manual car. Whichever is easier...
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Old 02-09-2015, 01:58 PM   #5
Rex34v
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Nice thread man how long did it take you to get it all done ?
& did the tranny mount up to the engine exactly ?
Planing to do the same but from a 02 to an 04
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Old 02-10-2015, 10:45 AM   #6
livid_wrx
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A lot of very interesting info here. Way more consolidated and to the point than other swap threads.

I too was tboned in my 02 wrx wagon and a friend of mine gave me his auto 02 wagon. He was planning on doing an STI swap and jumped on a rolling chassis that he got for a steal. Only problem is it's an auto and he didn't realize the pain in the ass it would be to convert ***128078;.

His loss, my gain.

So what I've gathered for my best plan of actuon is the following:

1. Swap out entire rear subframe.

2. Pull dash and replace entire dash harness and trans harness.

3. Replace entire steering column with components.

4. Drop trans, manaul ecu, engine and harness in.

5. Done.

Obviously easier said than done, but is this the gist of it? The most direct route without having to cut and splice wires? I'm not good at that and I'd like to avoid that head ache.
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Old 03-22-2015, 11:43 AM   #7
Titter
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following
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Old 03-25-2015, 11:41 AM   #8
Bikelok
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OP, great info and thread.

Considering how much time went into the conversion part of the swap, wouldn't it have been quicker (and easier) to just wait till you found a 5 speed car?

I'm not bashing at all as I feel it's fantastic people have done this swap and take the time to post to help others.

I guess the bottom line is, would you do it this way if you could do it over?
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Old 07-02-2015, 06:59 PM   #9
livid_wrx
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WRB

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Officially going the harness swap route.
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Old 07-02-2015, 07:25 PM   #10
jkenna860
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Quote:
Originally Posted by livid_wrx View Post
A lot of very interesting info here. Way more consolidated and to the point than other swap threads.

I too was tboned in my 02 wrx wagon and a friend of mine gave me his auto 02 wagon. He was planning on doing an STI swap and jumped on a rolling chassis that he got for a steal. Only problem is it's an auto and he didn't realize the pain in the ass it would be to convert ***128078;.

His loss, my gain.

So what I've gathered for my best plan of actuon is the following:

1. Swap out entire rear subframe.

2. Pull dash and replace entire dash harness and trans harness.

3. Replace entire steering column with components.

4. Drop trans, manaul ecu, engine and harness in.

5. Done.

Obviously easier said than done, but is this the gist of it? The most direct route without having to cut and splice wires? I'm not good at that and I'd like to avoid that head ache.
Yea man if you have all the harnesses and the ECU, then go that route. Electrical problems is A LOT harder to troubleshoot than mechanical... well at lease for me haha.

Right on GravelRash! That's cool that you shared your experiences of the swap with us. I wouldn't have imagined it being that complicated. But thinking about it now all the electrical sheet for the auto and yada yada totally makes sense. Im gonna go ahead and subscribe now
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Old 07-29-2015, 05:55 PM   #11
livid_wrx
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WRB

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I completed the full auto to manual with harness last weekend. I need to figure out ABS, but other than that it was a complete success! The thing about the ABS is I don't know if the sensor is bad, or if the unit itself if incompatible.

I'll be doing a full follow up here and in the other thread when I get a chance.
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Old 09-24-2015, 10:01 PM   #12
stevef.
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thanks for your input! I'm wanting to do this swap to my 07 forester and I'm trying to gather as much info as I can.
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Old 11-06-2015, 03:35 AM   #13
GravelRash
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Grime over Sedona Red

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And the thread goes on... Some miscellaneous replies...

Quote:
Originally Posted by Rex34v View Post
Nice thread man how long did it take you to get it all done ?
& did the tranny mount up to the engine exactly ?
Planning to do the same but from a 02 to an 04
All told it took me about 7 months - November to June, but there were a lot of factors involved:
  • Besides the swap I salvaged everything I could off the wrecked car, which involved everything up to a 4' prybar to accomplish. When the flatbed came for the old shell it was literally sitting on the garage floor; the driver hooked it with the winch and dragged it out and onto the truck.
  • I moved twice, including towing the car - rolling chassis, but nowhere near running...and having the nasty flu during the first move.
  • The old garage, at my house, was essentially heated by stray heat off the furnace and ductwork: soooo nice. The new garage - detached, at my apt., was just too damn cold to work in after the move - wearing long johns, jeans, heavy socks, t-shirt, pile jacket, fleece vest, heavy work jacket, and ski gloves. Bought a little 1500W heater that I could set under the car with me, and wondered why it didn't seem to be working; before I returned it to the store I realized that sucking 20deg F air in the back just wasn't going to result in nice toasty air out the front...
  • The occasional search through 2 garages and a storage locker for a tool or part...
  • Other stuff having nothing to do with car projects.

The tranny/engine combo wasn't an issue: I removed the engine/tranny (with installed Prodrive PPP3) from the wrecked car in one piece, partly 'cause I didn't want to deal with removing the tranny - with no clearance under the car to drag it out I'd have had to lift it out the engine bay anyway, and I was also swapping the engine/PPP3 as a known quantity.

That being said, there should be no problem bolting up the manual trans to the auto engine after you remove the auto flex plate and replace it with the flywheel/clutch from the manual motor. I don't think there should be any issue going from '02 - '04; basically the same engine and trans, and any changes along the way should have nothing to do with the engine/trans interface.

Quote:
Originally Posted by Bikelok View Post
...
Considering how much time went into the conversion part of the swap, wouldn't it have been quicker (and easier) to just wait till you found a 5 speed car?
...
I guess the bottom line is, would you do it this way if you could do it over?
I would certainly have preferred a 5spd car to start with but I was spending too much on car rental to want to wait around. Plus the replacement was the same color, one owner, all service records from the original (local) dealer...and how hard could it be? In hindsight it would have probably been easier - and maybe even cheaper - to just buy a cheap beater and wait for a good 5spd car, but that didn't occur to me 'til much later.

Quote:
Originally Posted by livid_wrx View Post
I completed the full auto to manual with harness last weekend. I need to figure out ABS, but other than that it was a complete success! The thing about the ABS is I don't know if the sensor is bad, or if the unit itself if incompatible.
Somewhere above I noted that the ABS units are NOT the same between manual and auto cars (contrary to earlier post(s?) in other threads). They're marked differently, right on top; all the logic is built into the units along with the mechanicals. That said, I have no idea whether that's actually related to your problem. I suspect that the auto unit would "work" in a manual car, but not optimally. Consider that the manual unit expects you to disengage the clutch before you stall the engine when braking, but the auto unit instead has to take the continuous auto power to the wheels into account as car speed approaches zero. May be subtle differences...but I wouldn't want to find out in the middle of an "OH, ISHT!!" moment!

stevef: Enjoy!
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Old 09-02-2019, 09:25 PM   #14
Dvpper_sf5
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Damn I know this is old as hell but if GravelRash is still around I PMd you man, I’m having a wiring issue with a swap of my own and I could certainly use some help.
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Old 11-04-2019, 04:12 PM   #15
CosmicChocolate
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thanks for the info guy im planing on doing this to my 02 rs but i got to get and engine for it first
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