jdm svx trans, will it work?

[b3lha]

Originally Posted by oab_au

Tom the bit that makes me think this is, the only things that know how fast the car is going, is the TCU and the speedo. I can"t see how the ECU could tell.
I think buried in among all the geek talk, there is a little routine that waits for the 187Kph to come up and pulls the torque control. Only having half the power, would produce a good speed limiter.

Another one for Phil, in his spare time.

Harvey.

No. That's complete and utter nonsense.

The ECU has a speed input. On the JDM and USDM cars, it comes directly from VSS2. On the Euro and Aussie cars, the ECU reads the speedo signal output from the TCU.

On speed-limited cars, the ECU turns the fuel off when the speed rises above 182km/h and back on again when it falls below 178km/h.

[Trevor]

Originally Posted by oab_au

Tom the bit that makes me think this is, the only things that know how fast the car is going, is the TCU and the speedo. I can"t see how the ECU could tell. Harvey.

N.B. A vehicle speed signal is routed to the ECU. The JDM ECU and speedometer both source a signal from the TCU.
The USDM ECU and speedometer, direct from a speed sensor.

P.S. Sorry Phil, I missed your reply which came up before I posted the above.

[oab_au]

Originally Posted by b3lha

No. That's complete and utter nonsense.

The ECU has a speed input. On the JDM and USDM cars, it comes directly from VSS2. On the Euro and Aussie cars, the ECU reads the speedo signal output from the TCU.

On speed-limited cars, the ECU turns the fuel off when the speed rises above 182km/h and back on again when it falls below 178km/h.

Oh well that sunk that theory..
Thanks Mate.

Harvey.

[subiemech85]

just read EVERY post

nobody mentioned a simple solution


USE a NOR gate

[Trevor]

Originally Posted by subiemech85

just read EVERY post

nobody mentioned a simple solution


USE a NOR gate

If you read carefully you will see that there are problems relating to the availability of a solenoid for the VTD. This is being attended to this very minute. Refer to the thread covering solenoids.

[Trevor]

I have purchased a JDM VTD solenoid for Alex as he has requested, but now have doubts as to whether this is in fact what he requires and have asked him for confirmation.
N.B. It appears that he is now working on advice given to him in a PM from Harvey.

just now, I have wasted one hell of a lot of time going back over everything in the thread. Let it be clear that in no way do I blame Alex for this, as there is a valid and understandable language problem.

#40 N.B. Alex states the tranny he has now, is from a US model and there is a binding problem and he needs a C solenoid.

#44 Alex advises he saved a lot buying the US tranny and requires a box(TCU) for the tranny and enquires regarding possibly using an ecutune. He received no direct reply regarding his query.

#47 Alex states he has to go back to the old plan and swap the tranny, and now just need the parts.
(He had been advised within the thread, that it was a pity not to have retained the original transmission, which is presumed to have been a VTD.)

Does all this mean/confirm that he is continuing with the US model transmission and therefore I have purchased the wrong solenoid? Or has he now had a change of mind and obtained a VTD transmission.

Alex has resorted to opening a new thread on the subject, but again there is continued confusion.

This is the most stupid and frustrating topic I have had to deal with. Once again I have found it necessary to spend much time correcting mistakes, which have again had a negative affect on members. This contrary to, and in contrast with, nasty words on the subject, recorded against me within the opposition forums.

[Trevor]

The saga continues.

I have now received a PM from Alex. He advises that he has, as I had presumed, a 4.44 transmission obtained from the US. I assume that this must be a centre clutch type rather than a VTD. This should have been fitted with the correct solenoid, I.e. a normally closed unit. If so his problem relates only to the TCU.

I am advising him further, and will endeavour to return/cancel the solenoid I have ordered.

So much for the incorrect information previously sent to Alex by PM, and on which he was relying. Lucky I have a few clues. I have told him, we will get him sorted in spite of the imposed problems. Surely that is what the network should be all about.

[BRADY]

Wow. Good work guys, I just read this entire post and was fascinated by the passion and hard work that was put it to finding a solution. I am also disappointed to read that there is mud being slung at members. We are all here because of our passion for the SVX - why must there be any negativity?

[TomsSVX]

Trevor, it is going to take a lot of work to get a US TCU to work with his car which is wired for the AU style VTD box. It does not have the same inputs for speed monitoring.

Tom

[Trevor]

Originally Posted by TomsSVX

Trevor, it is going to take a lot of work to get a US TCU to work with his car which is wired for the AU style VTD box. It does not have the same inputs for speed monitoring.

Tom

Tom, I have again been through this thread and now damn near know it off by heart. I have found the following as the nearest reference to the point you now bring forward. ----

TomSVX #41. A USDM TCU will fix the issue and be a lot easier to install. This would be (my) suggestion. Tom.

Alex-SVX #42 Ok thanks for the help. And this i must have from a US model of a Svx right?

I have to ask why was this can of worms not mentioned previously by someone, and not necessarily you? It looks like Alex is in the poo, a lot more than ankle deep.

[TomsSVX]

Originally Posted by Trevor

Tom, I have again been through this thread and now damn near know it off by heart. I have found the following as the nearest reference to the point you now bring forward. ----

TomSVX #41. A USDM TCU will fix the issue and be a lot easier to install. This would be (my) suggestion. Tom.

Alex-SVX #42 Ok thanks for the help. And this i must have from a US model of a Svx right?

I have to ask why was this can of worms not mentioned previously by someone, and not necessarily you? It looks like Alex is in the poo, a lot more than ankle deep.

I was not aware that he had the AU style trans before hand. I had made the assumption it was a JDM model with the front diff mounted speed sensor #2. I was corrected and agree that the solenoid is the only way to get rid of the binding he is dealing with. it may not be perfect but it will work

Tom

[Trevor]

Originally Posted by TomsSVX

I was not aware that he had the AU style trans before hand. I had made the assumption it was a JDM model with the front diff mounted speed sensor #2. I was corrected and agree that the solenoid is the only way to get rid of the binding he is dealing with. it may not be perfect but it will work

Tom

Please Tom,

If the normally closed C solenoid in the USDM transmission, *Alex now has fitted, is changed for a normally open C solenoid from a VTD transmission, the function of a signal from his current VTD TCU, will be reversed. e.g. An instruction to reduce clutch pressure, will result in an increase in pressure and vice versa. This is so, no matter which TCU is used.

(* It must be presumed that the correct solenoid was fitted when the transmission was supplied from the US.)

Although I have more than once carefully explained the reason for the difference in solenoids, this simple fact does not appear to be understood. This arrangement prevents an otherwise necessary and costly requirement during production, involving reversal the TCU PM signal, or to alternatively mechanical changes, as was claimed by Harvey.

As of now, the correct solenoid for the transmission fitted, and a signal from the present VTD TCU, will as reported, be causing problems. This due to the signal being programmed for a centre differential set up, rather than a clutch.

Trevor.

[TomsSVX]

Trevor, the problem is right now, the TCU is sending a signal to open the valve and reduce pressure when in fact the US solenoid is closing the valve and increasing pressure. If he fits the VTD solenoid with transfer valve, it will alleviate the pressure when the TCU commands it and supply it when it commands it. It is not the solenoid he needs at all in reality, it is the transfer valve body that he requires

Tom

p.s. I had a JDM VTD trans in a car that had gotten a 5mt swap. The transmission did bind in situations when it was meant to break the split between the wheels and did the opposite when it was to join them. The opposite valve body would remedy the issue at hand if I am right in that the difference is in the valve.

[Trevor]

Ok Tom,

This is an interesting one to sort out on the basis of available evidence. I have several important jobs to attend at the moment but will continue ASAP.

Meantime I am having a cup of tea, but it should be beer.

Cheers, Trevor.

[Trevor]

Originally Posted by TomsSVX

Trevor, the problem is right now, the TCU is sending a signal to open the valve and reduce pressure when in fact the US solenoid is closing the valve and increasing pressure.

Ok,Tom,

To help explain to Alex. ---

With the VTD TCU fitted in Alex’ SVX, when pressure is intended to be increased, a signal with an increased pulse length will be sent from the TCU, with the expectation of closing a normally open solenoid bleed valve. This would normally result in increased pressure and close the centre differential clutch to lock the centre differential.

The same increased pulse length (or a continuous) signal, when sent to the normally closed solenoid valve, now fitted in the US transmission in Alex’ car, will open the valve and reduce the pressure, opening the centre transfer clutch and provide only front wheel drive.

Fitting the special fuse, will have this same effect. N.B. This was fact was confirmed by alex in post #40 as follows.---
“when i insert the fuse in Diff Lock then the rear diff is not in use and the car could spinn on the front weal.”

If he fits the VTD solenoid with transfer valve, it will alleviate the pressure when the TCU commands it and supply it when it commands it. It is not the solenoid he needs at all in reality, it is the transfer valve body that he requires. Tom

There is no difference in the mechanical arrangements in respect of the two systems. As described above and as I have previously pointed out, the difference in solenoids takes care of the two different requirements, obviously with economical benefits.

No change of body or transfer valve is required and alternative components will not be available.

The VTD TCU and the USDM TCU will be programmed differently, in order to cater for the very differnt characteristics in respect of the LSD and the transfer clutch. As aresult the binding reported, could no doubt occur. Alternatively the used transmission which has been supplied, could be faulty. This certainly can not be ruled out.

p.s. I had a JDM VTD trans in a car that had gotten a 5mt swap. The transmission did bind in situations when it was meant to break the split between the wheels and did the opposite when it was to join them. The opposite valve body would remedy the issue at hand if I am right in that the difference is in the valve.

Your theory is unproven and is really only conjecture.

Yesterday you raised another matter:-

Trevor, it is going to take a lot of work to get a US TCU to work with his car which is wired for the AU style VTD box. It does not have the same inputs for speed monitoring. Tom

Phil, may be able to fill us in on this, provided he has had the patience to stay with the thread.

Alex has mentioned in a PM that he has done some wiring, but has provided no detail.

Where do we go from here?

Cheers, Trevor.