Transmission compatibility over year models

[McTaff]

Ok, I've seen so many differing claims on what year model trannies can go into an SVX... so:

Legacy/Liberty:
I am lead to beleive '92-'98 are ok.
What extra or different work is needed for a post '98 gearbox over and above what is already known for the earlier models?

Impreza:
Again, '92 - '98 are ok, correct?
What extra/different work is needed for post '98?

Ideal gearboxes:
The 6sp STi come out on top
WRX gearboxes are supposed to be strong,
Turbo Forester are supposed to be able to handle the load,
Liberty gearboxes are ok provided little modifications are done.

Anything I'm missing here? Can anyone group all the gearboxes into categories... for instance WRX and Forester Turbo I would assume are similar? This might help the dummies like me be able to pick the right gearbox out of the target zone, knowing what they are getting themselves into. Keep in mind that this applies to auto's as well, as some people may want to replace a busted SVX tranny with the auto from another Subie.

[SVXRide]

The issue with the 4HEAT boxes really is compatibility with the SVX's TCU. As the SVX was discontinued after the '97 model year, you have a high probability of "issues" if you try to use a 4HEAT out of any Subie newer than '97. I don't believe there are any issues with the 5 or 6 spd MT boxes - you just have to make sure you've jumpered the right leads out of the TCU to address idle and other issues (do a search of the site to find out exactly what they are....)
-Bill

[McTaff]

Weren't the newer models a different bolt pattern for the mounts or something???

For instance, I could use a manual out of a '02 Legacy/Liberty, right?

[tman6429]

My tranny in my 1992 SVX AWD is shot, i know finding the svx tranny is hard. I really don't wana convert it to stick. So what tranny would fit also. Direct bolt up. With small modifications to none. Thanks.

[oab_au]

that have the brake band, will plug into the SVX TCU. The later models, 4/5 speed, that use a clutch instead of the band, need their own TCU and a major rewiring to the TCU.

Harvey. ;)

[thundering02]

that have the brake band, will plug into the SVX TCU. The later models, 4/5 speed, that use a clutch instead of the band, need their own TCU and a major rewiring to the TCU.

Harvey. ;)

I think he was looking for a list of which to get and which to specifically avoid for that reason.

[tman6429]

So what tranny, (Automatic) can fit in an SVX awd. It seems like the original tranny is hard to find, is there different trannies from Subura cars or other cars that will fit directly??????

[SVXRide]

that have the brake band, will plug into the SVX TCU. The later models, 4/5 speed, that use a clutch instead of the band, need their own TCU and a major rewiring to the TCU.

Harvey. ;)

Harvey and I are saying basically the same thing....you'll be safe with a 4HEAT out of any other Subie as long as you stay with ones that came out of cars in the '92-'97 model years (I think '98 is safe also...)
-Bill

[Liquor Assassin]

what are the manual trannies to look for? when i get mine running im going to be looking for a manual to swap in. which have the best gear ratios, reliability, and are easiest to swap in?


and what is 4heat, sorry if thats a noobish thing to ask but hey.. im a n00b, bear with me

[McTaff]

and what is 4heat, sorry if thats a noobish thing to ask but hey.. im a n00b, bear with me

It's the 4 speed (E)lectronic (A)utomatic (T)ransmission.

Aussies call it the 4EAT. It's the same 4 speed auto fitted to almost all Subarus.

[McTaff]

that have the brake band, will plug into the SVX TCU. The later models, 4/5 speed, that use a clutch instead of the band, need their own TCU and a major rewiring to the TCU.

Harvey. ;)

Ooer. What sort of work is involved in that? I can get a '02/'03 Liberty auto and also a manual from the same year.

So, what is with doing either/or? I have two SVX's, and one will probably go to each (after sitting on the shelf for a while).

[Chiketkd]

It's the 4 speed (E)lectronic (A)utomatic (T)ransmission.

Aussies call it the 4EAT. It's the same 4 speed auto fitted to almost all Subarus.
McTaff,

One thing which people might be overlooking, is that you're a registered user in Sydney, Australia. The only SVXs imported there had the VTD 4EAT system.

As a result, an older 4EAT that uses a brake band system would NOT be compatible with your car. Your safest bet would be to get a 4EAT from a JDM Impreza WRX which also used the VTD system back in the mid 90's.

Any newer 4EAT should also work, as Subaru stopped using the brake band system in the '99 model year.

-Chike

[McTaff]

McTaff,

One thing which people might be overlooking, is that you're a registered user in Sydney, Australia. The only SVXs imported there had the VTD 4EAT system.
-Chike

(PM sent about this)

There is an interesting point.

Anyone have anything else to add for us poor Aussies?

[Chiketkd]

(PM sent about this)

There is an interesting point.

Anyone have anything else to add for us poor Aussies?
McTaff,

One thing which Huck pointed out in a separate thread, a VTD 4EAT equipped with Subaru's VDC system won't be compatible.

The VDC system was a sophisticated traction control system Subaru developed. The TCU for your VTD SVX wouldn't be able to control this 4EAT. Depending on the connectors, you may be able to swap TCUs, but I'm not sure of this...

-Chike

[oab_au]

As far as I know there is no other 4eat box that can replace the VTD box, that is in the Euro SVX with, I believe the B4 Liberty was the only other to use a VTD box like ours.
The Liberty that uses the Transfer AWD can be fitted as long as the doner TCU is replaced also. The TCUs operate the 'C' solenoid differently, and the Euros No.1 speed sensor is in the rear of the box, not on the front diff. The US versions allready have this TCU, so they are plug compatable, with the Legacy.

The later 4/5 speed boxs, with the clutch instead of the band, have to have there own TCU, as the gear box has a number of different componets and sensors, that would have to be wired or satisfied.
Harvey. ;)

[b3lha]

Let me confuse the issue a little more. The VTD trans in the UK/European (and possible Aussie) SVX has different speed sensors to the VTD trans in the JDM SVX and they are not 100% compatible. I think Harvey alluded to this in his previous post about Libertys.

Speed Sensor #2 is in the front diff on JDM models (like US models) and it has a separate 3 pin plug. But on UK models, the sensor is inside the gearbox and is wired through the big plugs with all the other transmission wires.

I believe that these sensors also produce different signals. On a JDM SVX, the signal wire branches out to the TCU, ECU, Speedo, and several other systems. On a UK SVX, the speed signal goes directly to the TCU and then comes out on another pin and branches to the ECU, Speedo and other systems. The service manual hints that the signal is modified in some way by the TCU.

I suggest you either rebuild your transmission or try to get one from an identical (year and market) car.

[oab_au]

Ooer. What sort of work is involved in that? I can get a '02/'03 Liberty auto and also a manual from the same year.

So, what is with doing either/or? I have two SVX's, and one will probably go to each (after sitting on the shelf for a while).

If you can tell which box the '02/03' Liberty used, we could have a look to see if it can be fitted. I can only tell the differences from looking at the wiring diag. It looks like there were two earlier(maybe 2000 models) 4 speed autos, both use the clutch instead of the band, the non-turbo, one has the Transfer AWD the turbo one has the VTD AWD.
The later(what year ?) 4/5 speed, are different again. Much more intergrated with the ECU, would be a lot harder to fit to the SVX. The 5 speed can have the Vehicle Dynamic Control fitted, this seems to be an option.

How to tell which it is? Look to see if it has the band adjuster, check the rear extension housing, the Vtd is longer than the Transfer mod.

All that said, the gear box that we have in the Australian SVX is the best of all. It doesn't have the flakey lining problem, it doesn't have the AWD problems, it doesn't have the front diff breakage problems. It does have the Varied Torque Diff, and 3.7:1 ratios(that reduce the heat problems) All it needs is servicing, oil, pick-up screen cleaned, band adjusted, every 100k.

This is the car that Fuji designed it to be. Not altered to suit a market.

Harvey. ;)

[oab_au]

snip>
I believe that these sensors also produce different signals. On a JDM SVX, the signal wire branches out to the TCU, ECU, Speedo, and several other systems. On a UK SVX, the speed signal goes directly to the TCU and then comes out on another pin and branches to the ECU, Speedo and other systems. The service manual hints that the signal is modified in some way by the TCU.

<snip.

Thats interesting Phil, the speed sensors are a magnetic pick-up, and this type of signal is very prone to interferance and deterioration. Shielded or twisted wires are used on most Subarus. Most cars now use the Hall effect pick-up to prevent this trouble. So maybe they decided to run the sine wave signal to the TCU to change it to a square wave, before sending it out again.

Harvey. ;)