The Subaru SVX World Network   SVX Network Forums
Live Chat!
SVX or Subaru Links
Old Lockers
Photo Post
How-To Documents
Message Archive
SVX Shop Search
IRC users:

Go Back   The Subaru SVX World Network > SVX Main Forums > Technical Q & A

Reply
 
Thread Tools Display Modes
  #16  
Old 07-16-2009, 08:05 PM
oab_au oab_au is offline
Registered User
Subaru Gold Contributor
 
Join Date: Mar 2001
Location: Coffs Harb, Australia.
Posts: 5,032
Significant Technical Input Registered SVX
Re: jdm svx trans, will it work?

Quote:
Originally Posted by oab_au View Post
Yes you will need a 3.7:1 rear diff, and swap the C solenoid for the US one. Then use the US TCU.

Harvey.
A bit late to do this now, so it is either swap the TCU with its "speed limiter" or do the C swap.

Harvey.
__________________
One Arm Bloke.
Tell it like it is!

95 Lsi. Bordeaux Pearl, Aust. RHD.149,000Kls Subaru BBS wheels.
97 Liberty GX Auto sedan. 320,000Kls.
04 Liberty 30R Auto Premium. 92.000kls.
Reply With Quote
  #17  
Old 07-16-2009, 08:26 PM
Hondasucks's Avatar
Hondasucks Hondasucks is offline
Subaru Technician
 
Join Date: Aug 2007
Location: Vancouver, WA
Posts: 1,512
Send a message via AIM to Hondasucks Send a message via MSN to Hondasucks Send a message via Yahoo to Hondasucks
Registered SVX
Re: jdm svx trans, will it work?

All you need is a circuit that will invert the signal going to the solenoid. Since on the JDM trans full power = AWD, not FWD as in the US model. Wouldn't be all that difficult, and probably lots easier than getting a JDM TCU. I'm sure I could come up with a circuit that would work, I'd just need some time!
__________________
1992 SVX LS-L #1222 Pearl White
1987 GL Turbo wagon, 5 lug conversion, D/R 5 speed (Rice killer)
1992 Dodge Ram 4x4 diesel (car hauler)
1968 Dodge Polara convertible (Camaro killer)
1990 Toyota Corolla FWD auto (330,000 mile grocery getter)
1986 VW Jetta
Reply With Quote
  #18  
Old 07-16-2009, 10:21 PM
TomsSVX's Avatar
TomsSVX TomsSVX is offline
Maniac modifier
 
Join Date: Dec 2003
Location: Branchburg, New Jersey
Posts: 15,489
Registered SVX Classic SVX
Re: jdm svx trans, will it work?

Quote:
Originally Posted by oab_au View Post
A bit late to do this now, so it is either swap the TCU with its "speed limiter" or do the C swap.

Harvey.
I thought the ECU was the speed governor for the JDM models?? Hence the code written into them for it and the JDM ECU having the hardware to make it work.

Tom
Reply With Quote
  #19  
Old 07-16-2009, 11:09 PM
Trevor's Avatar
Trevor Trevor is offline
Registered User
 
Join Date: Feb 2002
Location: Auckland, New Zealand
Posts: 5,223
Registered SVX
Re: jdm svx trans, will it work?

Quote:
Originally Posted by TomsSVX View Post
yes

The JDM trans' center diff works on an opposite method so when the TCU commands FWD the trans will apply AWD. You will need the JDM TCU. Whether it will plug right in is the only thing I am not sure of

Tom
Exactly which solenoid do you now have you fitted? JDM normally open, or US normally closed?

It is the different solenoid which reverses the “command” of the TCU signal. When using a JDM transmission, you must fit the appropriate C solenoid valve, i.e. one that is normally open and NOT the US one which is normally closed.

You should also be using the JDM TCU, otherwise as I have pointed out, the programming will/may not be correct, which is no doubt the current situation. The US TCU is programmed for a clutch, the JDM for a differential.
__________________
Trevor, New Zealand.

As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit!
Reply With Quote
  #20  
Old 07-16-2009, 11:11 PM
TomsSVX's Avatar
TomsSVX TomsSVX is offline
Maniac modifier
 
Join Date: Dec 2003
Location: Branchburg, New Jersey
Posts: 15,489
Registered SVX Classic SVX
Re: jdm svx trans, will it work?

would it not have the same effect and still maintain the proper programming if you simply used a JDM TCU?? This is the right way to do it in my mind

Tom
Reply With Quote
  #21  
Old 07-17-2009, 01:16 AM
Trevor's Avatar
Trevor Trevor is offline
Registered User
 
Join Date: Feb 2002
Location: Auckland, New Zealand
Posts: 5,223
Registered SVX
Re: jdm svx trans, will it work?

Quote:
Originally Posted by TomsSVX View Post
would it not have the same effect and still maintain the proper programming if you simply used a JDM TCU?? This is the right way to do it in my mind

Tom
Greetings Tom,

I agree that it is confusing, but no.

Please refer --- http://www.subaru-svx.net/forum/show...t=35942&page=4


Cheers, Trevor.
__________________
Trevor, New Zealand.

As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit!

Last edited by Trevor; 07-17-2009 at 01:20 AM.
Reply With Quote
  #22  
Old 07-17-2009, 05:48 AM
svxistentialist's Avatar
svxistentialist svxistentialist is offline
Jersey Girl
Alcyone Gold Contributor
 
Join Date: Mar 2001
Location: Ireland
Posts: 8,270
Send a message via Skype™ to svxistentialist
Registered SVX
Re: jdm svx trans, will it work?

Quote:
Originally Posted by herffstyle View Post
I have an update,
everything is installed, tranny, rear gears with SVX LSD.
I drove the car down the road and all was well at low speed, when i needed to turn it felt strange, kinda like a 4x4 truck in 4wd on pavement. So i belive the center diff is locked or something.
I dont really know how the center diff is set up in the JDM.
I am using a US Spec TCU.

other than that it accelerates quickly and shifts nicely.

Anyone have input?
Think the JDM TCU will fix it?

Thanks
Steve
Steve

Aside from the debate about whether you should be using a US spec Sol C or a JDM spec Solenoid C, I'm of the opinion you should be using a JDM type TCU to control that gearbox.

The TCU has different maps for each gear It uses a large range of data inputs to ensure traction works, and that it works in tandem with your ABS. Essentially you are now using [US] maps that vary traction from 10% rear standard mode to 50% rear under hard acceleration which is the US gearbox specs.

These US traction maps are incompatible with the gearbox you now have fitted, which has normal standard distribution to the rear of 64%, varying upwards to 50% under hard acceleration [VTD maps, JDM traction control]

Were you to completely disconnect the signal to Solenoid C, I would suspect in default mode your gearbox should operate permanently at 36% front and 64% rear and be entertaining to drive. I'm wondering if perhaps with the signal your American TCU is getting from the Solenoid C that the incompatibility issue may be causing it to lose its marbles and go to 50/50 lock up?

Also, the symptoms you describe sound like 50/50 centre diff lock-up. Please check if the fuse is inserted under the hood. In the US cars, inserting the fuse causes 100% front wheel drive, and does no harm. With the JDM gearbox, inserting the same fuse locks the centre diff 50/50, and will do harm if you keep driving in that mode.

My best advice is you need a JDM style TCU. Even the UK/OZ type will be less than ideal. It will have the correct traction maps but uses different speed input data.
BUT CHECK THAT FUSE IS NOT INSERTED!

Joe
__________________
Black Betty [Bam a Lam!] '93 UK spec, still languishing Betty
Jersey Girl Silver '92 UK [Channel Isles] 40K Jersey Girl @ Mersea
Candy Purple Honda Blackbird Plum Dangerous
White X2 RVR Mitsubishi 1800GDI. Vantastic

40,000 miles Jersey Girl
Reply With Quote
  #23  
Old 07-17-2009, 02:16 PM
Trevor's Avatar
Trevor Trevor is offline
Registered User
 
Join Date: Feb 2002
Location: Auckland, New Zealand
Posts: 5,223
Registered SVX
Re: jdm svx trans, will it work?

Joe,

Please do not add to the confusion. There is no debate regarding the different C solenoids fitted to the US clutch system and the JDM and others using a centre LS diff. Without doubt, the solenoids are different as has been stated. The reason is clear and not difficult to assimilate.

Trevor
__________________
Trevor, New Zealand.

As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit!
Reply With Quote
  #24  
Old 07-17-2009, 02:40 PM
svxistentialist's Avatar
svxistentialist svxistentialist is offline
Jersey Girl
Alcyone Gold Contributor
 
Join Date: Mar 2001
Location: Ireland
Posts: 8,270
Send a message via Skype™ to svxistentialist
Registered SVX
No debate?

Quote:
Originally Posted by Trevor View Post
Joe,

Please do not add to the confusion. There is no debate regarding the different C solenoids fitted to the US clutch system and the JDM and others using a centre LS diff. Without doubt, the solenoids are different as has been stated. The reason is clear and not difficult to assimilate.

Trevor
Hey Trevor, I thought I was elucidating on the subject.

No debate on the C solenoids? You could have fooled me. When you have Tom and Harvey and you, and a couple of others to boot, throwing in suggestions that differ, I take that to be a debate, am I mistaken?

Plus I think Tom and you and I have essentially said the same thing, use a JDM type TCU? Hopefully that does not add to the confusion.

Joe
__________________
Black Betty [Bam a Lam!] '93 UK spec, still languishing Betty
Jersey Girl Silver '92 UK [Channel Isles] 40K Jersey Girl @ Mersea
Candy Purple Honda Blackbird Plum Dangerous
White X2 RVR Mitsubishi 1800GDI. Vantastic

40,000 miles Jersey Girl
Reply With Quote
  #25  
Old 07-17-2009, 03:15 PM
TomsSVX's Avatar
TomsSVX TomsSVX is offline
Maniac modifier
 
Join Date: Dec 2003
Location: Branchburg, New Jersey
Posts: 15,489
Registered SVX Classic SVX
Re: jdm svx trans, will it work?

Quote:
Originally Posted by Trevor View Post
Greetings Tom,

I agree that it is confusing, but no.

Please refer --- http://www.subaru-svx.net/forum/show...t=35942&page=4


Cheers, Trevor.
It just makes no sense. If you have the JDM trans and a JDM TCU it will essentially be a JDM car (not m4[) jdM y0). So unless there is a problem with the way a JDM performs, it is incorrect to us a US solenoid in a JDM trans with a JDM TCU

Tom
Reply With Quote
  #26  
Old 07-17-2009, 03:22 PM
Trevor's Avatar
Trevor Trevor is offline
Registered User
 
Join Date: Feb 2002
Location: Auckland, New Zealand
Posts: 5,223
Registered SVX
Re: No debate?

Quote:
Originally Posted by svxistentialist View Post
Hey Trevor, I thought I was elucidating on the subject.

No debate on the C solenoids? You could have fooled me. When you have Tom and Harvey and you, and a couple of others to boot, throwing in suggestions that differ, I take that to be a debate, am I mistaken?

Plus I think Tom and you and I have essentially said the same thing, use a JDM type TCU? Hopefully that does not add to the confusion.

Joe
There is no debate and simply incorrect statements by Harvey.

I have proven what I have stated is fact with detailed information. If in doubt please physically check your own cars which have a centre diff. The C solenoid will close when energised, i.e. it is normally open. Also refer post in the opposition forums from a member from Norway, requiring a C solenoid.

Trevor
__________________
Trevor, New Zealand.

As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit!

Last edited by Trevor; 07-17-2009 at 03:34 PM.
Reply With Quote
  #27  
Old 07-17-2009, 03:33 PM
TomsSVX's Avatar
TomsSVX TomsSVX is offline
Maniac modifier
 
Join Date: Dec 2003
Location: Branchburg, New Jersey
Posts: 15,489
Registered SVX Classic SVX
Re: jdm svx trans, will it work?

More or less I think we are all saying the same things, just mixed it all up. From what I have gotten from all this and my understanding of how they all work here are a couple scenarios

Trans-TCU- SOL C
US-US-US
JDM-JDM-JDM
JDM-US-US
US-JDM-JDM

basically as long as the Sol C. Matches the TCU being used it will function properly. Thats my understanding and why anyone would need to make it more complex is complex in itself

Tom
Reply With Quote
  #28  
Old 07-17-2009, 03:41 PM
Trevor's Avatar
Trevor Trevor is offline
Registered User
 
Join Date: Feb 2002
Location: Auckland, New Zealand
Posts: 5,223
Registered SVX
Re: jdm svx trans, will it work?

Quote:
Originally Posted by TomsSVX View Post
More or less I think we are all saying the same things, just mixed it all up. From what I have gotten from all this and my understanding of how they all work here are a couple scenarios

Trans-TCU- SOL C
US-US-US
JDM-JDM-JDM
JDM-US-US
US-JDM-JDM

basically as long as the Sol C. Matches the TCU being used it will function properly. Thats my understanding and why anyone would need to make it more complex is complex in itself

Tom

The TCU and solenoid must match the transmission. i.e. US-US-US, or JDM-JDM-JDM, are the only arrangements which will work correctly.
__________________
Trevor, New Zealand.

As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit!

Last edited by Trevor; 07-17-2009 at 03:49 PM. Reason: Addition.
Reply With Quote
  #29  
Old 07-17-2009, 03:46 PM
TomsSVX's Avatar
TomsSVX TomsSVX is offline
Maniac modifier
 
Join Date: Dec 2003
Location: Branchburg, New Jersey
Posts: 15,489
Registered SVX Classic SVX
Re: jdm svx trans, will it work?

Thats what I was saying originally but you told me it required a US solenoid if you were going to use a JDM trans and TCU... hence the confusion... Maybe I just read it wrong

Tom
Reply With Quote
  #30  
Old 07-17-2009, 04:00 PM
Trevor's Avatar
Trevor Trevor is offline
Registered User
 
Join Date: Feb 2002
Location: Auckland, New Zealand
Posts: 5,223
Registered SVX
Re: jdm svx trans, will it work?

Quote:
Originally Posted by TomsSVX View Post
Thats what I was saying originally but you told me it required a US solenoid if you were going to use a JDM trans and TCU... hence the confusion... Maybe I just read it wrong

Tom
Please Tom,

If in any way I posted a confusing statement advise where, so that I may quickly apologise and correct same. Throughout my aim and intent has been to retain accuracy within the thread, in order to prevent the annoying confusion which has been established as a result of incorrect statements.

Sincerely, Trevor.
__________________
Trevor, New Zealand.

As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit!
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 04:13 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
© 2001-2015 SVX World Network
(208)-906-1122