2000+ WRX Automatic Transmission Compatibility
 

Please don't write me nasty letters or burn me at the stake for even considering this, but I'm considering putting a 2000-something WRX automatic transmission behind a 92 SVX engine. See, it needs needs a tranny, and I can get a free transmission for it. If it wasn't free I'd be going the manual route, but free is just such a darn good price.

My question is whether or not there are any special considerations to putting that transmission behind an EG33. It should bolt up, it should handle the power, and the wiring harness should be the same, (or at least have the same wires, even if I have to splice them into the old connector.) Am I missing anything?

Unfortunately, I don't have many details about the WRX transmission other than what I've already mentioned. It was supposed to have come out of a working car in Japan, but it's passed through several hands so the story may be wrong.

If anybody has any red flags to raise, please do; I'm all ears.

I'm pretty sure it needs a different TCU if it has VTD like our WRXs do. you might need a rear diff too if the final drive is different.

that's all I got. I'm sure others will have more.

What he said. The REX 4HEAT uses the VTD center diff. Not sure how that's going to work with the USDM SVX TCU that was designed for the clutch type center diff. You may want to consider finding a JDM SVX TCU because the JDM SVX used the VTD center diff. I'd love to see this happen. The VTD is cool.

Yeah, I thought having an actual center differential was pretty cool too. I can't think of any reason why the clutch in the VTD would require different input than the transfer clutch in the SVXs. Perhaps it might require less input, but I would think the clutches would be sized accordingly, so even that might not be an issue. If it causes me any troubles, I'll just disconnect it and ignore the power light. :)

I think what I'm most concerned about is if there is anything physically different, such as being longer or having a different bell-housing, or different starter motor mount, etc.. If the WRX transmission does not have all the same inputs and outputs, (i.e., the same wheel speed sensor, temperature sensor, three shift solenoids, and three duty solenoids,) that could be a hassle, but I should be able to work around that. I'll find a wiring diagram and compare.

That would be cool having the VTD.

Has anybody done this swap?


Also, it was raining cats, dogs, and livestock today. I love all-wheel-drive! Powerslides are sooooo much more fun when the rear follows suit.

PM Kha0s, RiftsWRX, or Hunter001 on Nabisco. Legacy777 might know something too, but I think he knows more about MPT autotrannies.

there are a number of physical differences. the most obvious being the extra planetary gearset. I'm pretty sure the whole unit is longer too. beyond that, I know a lot about the capabilities of it, but not so much about the physical aspects of it.

<speculation>
I agree that the clutch in the VTD ought to work well with the types of commands that are sent to the MPT. I'm wondering if the signalling and wiring harnesses are the same though. On the more positive side, my guess is that the physical dimensions (at least for purposes of installation) are identical to the SVX 4eat.

The SVX 4eat TCU wiring diagram is online here:

http://reaper450128.homeftp.net/servicecd.htm

If you can find a WRX 4EAT wiring diagram, you can probably get a better idea of compatibility.
</speculation>

I really hope this works out for you as I would consider doing this at sometime in the future also, :)

A longer WRX tranny could be a problem. I am not sure how you would shorten the propellor shaft.

For my application, drive shaft length just isn't going to matter. What I was hoping is that I might be able to adapt the transfer housing onto my working SVX, as I don't intend to use the transfer housing on the WRX transmission. Don't ask... :)

In any case, as long as the transmission and engine bolt together, I think it'll work.

I expect it will work for you too.

The main problem I see is that the final drive is almost certainly lower in the tranny from the WRX, than it is for the SVX. The US model has even longer legs than the Euro or JDM spec, and I suppose that relates to the expected long range on-highway driving you guys do a lot of.

Even if the box is free, you are going to have to source a compatible rear drive to suit.:(

Hope it all works out. With a lower final drive, you will have much more fun with the car.

Joe:)

Looks like I'm going to have to figure out exactly what that transmission came from. Subaru made several changes to the 4EAT between 1998 and 2002, (which is roughly the year of manufacture for the transmission in question,) including a few extra solenoids and speed sensors. Looks like they made some pretty neat improvements actually. The SVX TCU wouldn't do justice to some versions, but it might do the job anyway.

Since it looks like it'll bolt up, I don't have any excuses now except parting with money for the rest of the project. If anybody knows of a great source of wiring diagrams and a way to identify the transmission via serial number, that'd be helpful. I'm probably going to need to visit the dealership with a case of beer and puckered lips.

I noticed that the CV shafts for the L-series are different depending on weather it's a turbo or non-turbo model. The turbo CV splines on the tulip don't fit on the side gear output shafts on the non-turbo transmission - they're too big. Did Subaru standardize the spline size somewhere along the way? I hear about 5MT, 6MT, Legacy 4EAT, and Impreza 4EAT swaps, and nobody seems to have any problems with the CVs mating up. Just wondering.


Oh yeah. I understand low gearing would liven things up, but I like those super-steep gears. More power is the way to go. :) I'll, ummm, uh, let you know when I find a way to get some.

Well, I ended up getting the donor car with the engine, bad transmission (installed), and good spare transmission. It seems the spare transmission is from an early 90's Legacy. That transmission may work, but I'm not super keen on using it as it's been cracked open and left sitting; plus it probably doesn't have the center differential, though I haven't looked into it to be sure. In any case, I don't think I'm going to use it.

The donor car is the black one.

The current transmission doesn't want to shift out of first gear. I don't think the AWD is working either. Reverse works just fine. I'm not getting any ECU or TCU trouble codes on this car at all! I'm thinking this is a mechanical problem. Has anyone else had this problem?

Have you tried going through the gears manually instead of using D?

a 2000+ uses a different TCU, the bolt pattern is different, the shifter linkage is different, it would be probably as costly a conversion as doing a 5mt swap but you have the transmission so that cuts that cost

if you were ready to shell out a couple thousand to convert the car to a manual then you may as well, the new one is stronger, and has a better center diff setup

Yes, I tried going through all the gears. I even put it in second and put it in manual mode, which should force it to stay in second all the time. ...no luck. Incidentally, it'll do 55 in first. :)

I still have some things to check on the current transmission. I haven't had time to look at it yet, but I wonder if the gear selector switch may be bad. If the switch is stuck in first, that would explain why there are no codes. I'll disconnect the TCU, as that should make it default to third gear, which will tell me if the problem is mechanical or electrical.

I'm pretty sure I'll end up pitching the spare transmission. It looks like it's seen better days. I'll have to give it a good once-over before I do, but the prognosis doesn't look good.

I'm not really looking for a manual transmission. I strongly prefer that this engine continue to use an automatic. Does anybody have a complete list of all the internal changes that the 4EAT underwent over the years?

Also, this car has three driver's-side wheels and only one passenger-side wheel. Anybody have the opposite problem that wants to trade? I'll post this question elsewhere, but I thought I'd throw it out there.