Legacy gearbox option

[DJW svx]

Although I'm about to change the oil in the autobox with Amsoils finest I would like to know what Legacy gearbox is suitable for the SVX bearing in mind mines the JDM model if that makes any difference as I have seen many for sale on e-bay and I think if my box goes I'll go straight for this type of replacement.

[svxistentialist]

It's a pretty cheap option if you do it right, but a minefield.

We probably need to design up a flow chart or something that will deal with all the options.

I don't know how savvy you are about auto transmissions, so please bear with me if some of the following seems pedantic.

There are two types of 4EAT gearboxes used by Subaru:

1. VTD type
2. ACT4 type

The UK SVX and the Japanese SVX and the Australian SVX all come fitted with the VTD type which is by far the better gearbox.

The USA SVX and the German SVX both come with the ACT4 gearbox, which effectively has an electric clutch sending drive to the back. It is similar in principle to the Honda system used in the 90s CR-V, being a primarily front drive transmission with rear assist. Except it is 100 times better than the Honda system.

Even though the UK and JDM use the same type of gearbox the application is different because the Japanese gearbox uses a speed sensor driven from the front differential, and in the UK cars the second speed sensor is inside the gearbox. [The Aus version of the SVX is the same, with internal sensors]

This might look like a small difference but what it means is to use the Japanese gearbox in the UK car you would need to rewire the transmission at least. Effectively it's worse than this, you actually have to install the same year Japanese TCU [Transmission Control Unit aka transmission computer] to make it work, and even this will need some wiring changes.

So to install the transmission from a different type of UK Subaru car you will need to be aware of the differences above, or it will give you grief.

In addition to this the SVX has a rare or possibly unique final drive of 3.70 in England. To make the gearbox slot in and work the sourced box from another Subaru will need to have the same final drive as the SVX does. If it does not, then you will also have to change the rear differential to one that has the same final drive as the gearbox you are buying.

In the Subaru world there are a number of different final drives available for auto transmissions:

• 3.54 very high final drive for US type SVXes. Not normally available here.
• 3.90
• 3.70. Standard for UK, Australia and Japan SVXes.
• 4.111 Available on some Legacies. And JDM Legacy twin turbo.
• 4.444. Very low final ratio. Forester Turbo.

I'm not trying to make this option look difficult for you. [I don't need to. It is difficult to buy a plug and play gearbox for the SVX.]

I'm just setting out the markers so you don't get a rush of blood to the head and buy something off flea bay that will be difficult or impossible to get working.

Joe

[DJW svx]

Thanks for the reply and it is a bit of a minefield, the other option would be a manual is that more straightforward?

[svxistentialist]

Originally Posted by DJW svx

Thanks for the reply and it is a bit of a minefield, the other option would be a manual is that more straightforward?

Yes, it's a bit of work but is easier to do than adapt a different type of auto. You will need to fit the foot pedals from the donor car, bolting up the clutch and bell housing is relatively straightforward, and you need to remove the auto shifter from the console and replace with a professional looking Manual shifter and gusset so as not to let down the quality of the interior.

You have to do a little with electrics and electronics because the ECU is connected to the TCU and "expects " to see a Neutral or Park signal to allow the engine to start and run. There are a couple of get-arounds for this.

If you are buying a manual you can go for a 5 speed or a 6 speed. Be careful in your choice of later Sti boxes though. If you buy one that has the differentials electronically controlled though, known as DCCD type, then you are back in the minefield. You would be needing a tame electronics guru and probably the programming from the ECU of the donor car, which will be 4 pot, and not capable of managing 6 cylinders.

In short, avoid DCCD gearboxes unless you are the type that likes challenges.

Joe

[DJW svx]

Thanks again, Looks like I'm going to have to put a lot of faith in the Amsoil fully synthetic oil, and after meeting a fellow SVX owner Gez with the silver one on Hayling Island I'm going to have to find someone who can remove all the oil from the box rather than the 3 litres that comes out from removing the plug. Has anyone tried to duct air through to the box from one of the front mounted slots on the lip? just a thought.
The car is looking tidy now as I've had all the dinks and scrapes removed had the roof and boot re-sprayed black and also decided to have the wheels refurbed as they were a bit rough. Hopefully we will arrange the photoshoot/meeting shortly and post up some pictures.

[svxistentialist]

Originally Posted by DJW svx

Thanks again, Looks like I'm going to have to put a lot of faith in the Amsoil fully synthetic oil, and after meeting a fellow SVX owner Geff with the silver one on Hayling Island I'm going to have to find someone who can remove all the oil from the box rather than the 3 litres that comes out from removing the plug. Has anyone tried to duct air through to the box from one of the front mounted slots on the lip? just a thought.
The car is looking tidy now as I've had all the dinks and scrapes removed had the roof and bonnet re-sprayed black and also decided to have the wheels refurbed as they were a bit rough. Hopefully we will arrange the photoshoot/meeting shortly and post up some pictures.

That sounds like good improvement in a short time.

The usual way to change all the oil in the box is to refill with the new oil, run it for a week or for a month, then change the oil again. This way you will have most of the oil in the transmission brand new and good.

You can then choose to refresh it again at 6 months, people who are really fussy do this, but in truth changing again at 12 months is more than adequate.

Regards ducting cooling air through from the nose, this has been mooted. I mentioned it myself last year after noticing the amount of heat leaking to the cabin when my aircon was down while over in England. My idea was more about shifting the warm air between the gearbox casing and cabin floor though, rather than as an active way to keep the gearbox cool. I believe the additional transmission oil cooler can do way more to keep the box in the correct operating temperature range than cooling air from the nose could, but everything helps.

Looking forward to your photos.

Joe

[DJW svx]

I think I'd rather try to drain the lot as the Amsoil cost over £120 for the 10 litres so rather than dilute it I think it would be better to opt for complete draining if practical. The ATF oil was only changed about 20k kilometres ago according to the sticker so if I work on the basis that this has flushed the box nicely its about ready for the Amsoil.
Once I've had a root around underneath I may come up with some kind of blade to duct the flow that goes under the car to the box as its not exactly low at the front.

[Alex-svx]

I say not use US model on European car. I have just done this on mine and still will not work 100% Its have better whit the C-solendion change.

So if you want something that work so use the VTD type.

[DJW svx]

Originally Posted by Alex-svx

I say not use US model on European car. I have just done this on mine and still will not work 100% Its have better whit the C-solendion change.

So if you want something that work so use the VTD type.

Thanks for the reply, I'm going to put my faith in the ultra expensive oil for the moment and have a look at innovative air ducting/diverting (well it'll keep me off the street corners for a while anyway)

[AJAS]

Have you thought about fitting a front-mounted transmission cooler? My Skyline had one and had no problems with the box in 100k miles and the oil never got changed.

I was looking to fit one on my JDM Legacy GTB and was surprised at how many specialists there are around that will fit them. Kenlowe do kits - I think a universal item - which was in the order of £115 excl fitting. Haven't investigated further yet.

Not sure whether there would be room to route the pipes thro the engine bay - pretty tight, from memory of changing the plugs! On the Legacy, there is a filter just behind the headlight, so a much easier fit!

[DJW svx]

Thats worth looking in to once I've done the oil, but is there an issue with Jap domestic market cars with the auto box?

[svxistentialist]

The gearbox in all SVXes tends to be a weak point, and the Japanese sourced cars are no different.

With the later gearboxes from 93 or 94 there were some modifications by Subaru [or Aisan] internally, enlarged oil passages and stuff. Most people like to have the modified gearboxes naturally, but it is quite possible to have an early [92] car and be still running the original gearbox at well over 100K miles, depending how it was cared for and indeed where and how it was used.

Most early unmodified gearboxes will die at 70K and need a rebuild. What makes them fail is the exceptionally high oil temperatures that can be reached internally. These temperatures burn up the clutch friction materials, slippage happens over time, clutches burn out and lock up.

The OEM oil cooler in the left lower corner of the rad is a good device in the sense it allows the oil to warm up quickly to operating range by contact with the warmed coolant. However it is not good enough to get rid of the really high temperature spikes that kill the oil and burn the clutches.

That's why any gearbox with the additional oil cooler and whose owner is religious about keeping the oil changed and fresh will last the distance, regardless of whether it's the upgraded type or not.

And never, never ever reverse flush or power flush the oil from the gearbox. Always make do with draining while hot and making do with what drains out by gravity.

Reverse flushing/power flushing dislodges loose particles from the oil cooler [which acts like a sort of broad filter, catching impurities over time] which get back to the box into the fine oil passages, resulting in gearbox burn out, usually within weeks.

Joe

[DJW svx]

So I guess I should just start changing and replacing with the Amsoil and perhaps consider buying a further 5 litres so that over the period of say 4 or 5 changes the Amsoil will be more or less undiluted not quite what I had in mind but perhaps the best way to prolong the life of the box.

[svxistentialist]

You put too much faith in the Amsoil, although it's a great product.

Any fully synthetic will do as they are more resistant to heat for a longer period. Just put the additional cooler on the gearbox oil, and change the fully synthetic once or twice a year, and you have no worries. It will last as long as it's going to last.

Remember that if the clutches are heat damaged or burnt up by its first mileage in Japan, you can't turn back that clock. The best you can do is a maintenance job, hold it in that condition and take care of it.

Good oil and a good cooler is all it needs. Give it that then enjoy driving it till it eventually needs a rebuild.

[DJW svx]

Yes you're right there, another SVX owner Gez has given me the details of a local guy who specializes in auto-box's and knows SVX's so I may well go along and get an additional cooler fitted. As you rightly say if its been cooked in Japan I'm stuffed but at least a bit of pro active work may help.
Having now driven the car for a few weeks I do like it, my daily route is the A272 which is popular with motorbikes and sports cars and the SVX just wafts effortlessly along this twisty A road with great ease.