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 > MOD Mania > Transmission and Drivetrain

Reply
 
Thread Tools Display Modes
  #1  
Old 04-21-2015, 08:34 PM
AirTech90's Avatar
AirTech90 AirTech90 is offline
Registered User
 
Join Date: Mar 2015
Location: Richmond, Illinois
Posts: 14
Registered SVX
New guy needs advise for a 4.44:1 VTD build

Hello all..

I recently, about a month ago, bought my first SVX. It is a 94 LSi, emerald green, with just over 84k miles on it, and in pretty good shape, so far, for the price I paid for it, in my opinion. Prior to this, I had not even known that the SVX existed. I have been a fan of Subarus in general for a few (several) years now, yet I have never owned one, personally. I was actually looking for a Baja turbo, but, this was a case of accidentally tripping over one and saying.."OMFG, WTF is that?".."Its basically an STI limited, 2 door, with a 6cyl. EJ3.3 that has the good crank bearing journals vs an EZ engine, and a 4eat, and its AWD? with cool windows and a Delorian body with paint"..."I need one!"...lol...it just so happened that I had the funding and the price was right and so, I now feel like Im 30 years younger, when I bought a '74 AMX 401 Javelin under similar circumstances...lol...
I am continuously doing research on the SVX through these forums mainly (this one more than the other, but I do try to include all available, relevant resources and cross check info ), since the day I bought it, as I did due diligence in researching this car before I pulled the trigger on the sale. No need to spell out what Ive found online, here, where you know better than I.
I am a mechanic by trade. I have been, for the past 34 years. BUT, I have been an aviation mechanic, specifically, since 1990. This is relevant because, as I might understand the theory behind an application, I dont have the hands on experience and access to specific tools and resources that an auto mechanic might be expected to have. for example, we dont use floor jacks on airplanes, much less impact drivers or car lifts, so, please bear with me. Any work that i choose to do myself would necessarily be done in an aircraft hanger, and some jobs I would simply prefer to "farm out" rather than tie up that hanger. Its a matter of logistics rather than competence...lol..point being, I can do a "power mod" in about 5 min.s, but changing a 250 pound transmision, solo, might go beyond my "will vs pocketbook", equation. Im not lazy, just "end result" oriented. I am a piston engine overhaul specialist, and I truly appreciate the value of experience over first time "follow the manual" jobs.
OK, being that this is my first subjective post on this forum, and having gotten that primary introductory background info out of the way, we get to the meat and potatoes.
My ultimate goal is to install a 4.44:1 trans. and diff., with a VTD center.
I understand that this is potentially somewhat of a project on a USDM SVX.
My strategy is, at this point, to do the 4.44:1 swap from a USDM '96-'98 legacy/outback to get the gearing in place first, along with a QC module and power mod.,. using the existing USDM SVX TCU and SVX torque converter.
From here on, comes the questions.
Can the JDM/Aussie VTD rear housing be transferred to a USDM trans. if the TCU is changed out/or not? or, would I need to swap the entire trans. and swap in the ring and pinion gears to the JDM/Aussie trans/TCU combo? I am aware of the trans. mount issue with the VTD tail section, and have the part numbers for those already. Are there issues with that gearing vs. the TCU's that need to be addressed?
I have noticed that there is an existing 4.44:1 VTD trans setup out there...and I believe it has a QC mod too....lol...
.
Reply With Quote
  #2  
Old 04-22-2015, 08:30 AM
AirTech90's Avatar
AirTech90 AirTech90 is offline
Registered User
 
Join Date: Mar 2015
Location: Richmond, Illinois
Posts: 14
Registered SVX
Re: New guy needs advise for a 4.44:1 VTD build

ok..let me be a little more specific about my concerns..

I understand that a Phase 1, USDM 4EAT 4.44:1 trans from a 96-98 outback, not only has the different ring and pinion gear ratios, but also has different 1st and 2nd gear ratio's internally, than the stock SVX 4EAT. but if Im not mistaken, there are no problems with using the stock USDM SVX TCU with that trans., as far as shift maps, sensors etc., all the wiring is plug-n-play. I also understand that it is best to retain the use of the SVX torque converter if possible...And of course the rear differential gearing swap, but that is pretty straightforward and not where my questions lie......correct me if Im wrong at any point, please.

OK, now...once that assembly is ( in theory) installed. From what I understand, the VTD tail section from a JDM or Aussie, Phase 1, 4EAT, can be swapped in to replace the original center diff., BUT, because of the difference in how the c-solenoid is utilized, and the difference in the speed sensor in the tail section, the TCU from a JDM/Aussie 4EAT, along with the rear trans/cross-member mounts, must be used. And the wiring for the speed sensor may need to be modified.

I am making a leap of faith, that the TCU from a JDM/Aussie 4EAT will "play nice" with the different 1st and 2nd internal gearing of the USDM 4EAT from an outback., as far as shift maps, etc. are concerned. If not, then, the other option would be to remove the ring and pinion gears from the front diff. of the outback trans., and install them in the JDM trans., and use that entire assembly. (trans. and TCU) potentially still requiring a modification of the speed sensor wires.

I would, of course, prefer to simply switch the tail sections and TCU, if its possible, for the sake of simplicity and cost.

If there are any flaws in this plan, or details I am missing, any advise would be greatly appreciated.

Thanks for reading through all my gibberish...lol...and thanks in advance for any insight you can provide.
Reply With Quote
  #3  
Old 04-22-2015, 10:45 PM
Tapani Tapani is offline
Registered User
 
Join Date: Feb 2010
Location: Finland
Posts: 815
Registered SVX
Re: New guy needs advise for a 4.44:1 VTD build

I bought a 1996 JDM tranny (3.70), sourced a 3.70 rear diff, already had a modified TCU with a removable ROM for the firmware. Then sourced a ROM with the correct JDM firmware.

While at it I installed a Quaife Torsen torque biasing diff at the rear and a Modena (similar operation principle) at the front.

I like the set up very much. With a bit stiffer/lower springs, Koni dampers and a 19mm rear sway bar the handling is neutral.

If you really want the lower gearing then you need get the maps modified. Starting with the JDM firmware may be the easiest way forward. You may also find a low mileage JDM tranny in good working order - I did. Claimed 55.000 kms..... so far so good - two years with a turbo charged engine including occational track days - no problems.

Kind regards from Finland,

Tapani

Last edited by Tapani; 04-23-2015 at 10:12 AM.
Reply With Quote
  #4  
Old 04-23-2015, 11:53 PM
1986nate 1986nate is offline
Senior Member
Subaru Silver Contributor
 
Join Date: Sep 2008
Location: Meadville, PA-but I'll still travel
Posts: 4,672
Registered SVX
Re: New guy needs advise for a 4.44:1 VTD build

quite simply put, for a VTD swap, you not only need the VTD parts, but the c solenoid type must match the VTD TCU as Subaru changed C solenoid operation for VTD transmissions sometime in 95.
Along with that, you need VTD rubber transmission mounts, they are very different.
Reply With Quote
  #5  
Old 04-24-2015, 12:24 PM
AirTech90's Avatar
AirTech90 AirTech90 is offline
Registered User
 
Join Date: Mar 2015
Location: Richmond, Illinois
Posts: 14
Registered SVX
Re: New guy needs advise for a 4.44:1 VTD build

Thanks for the responses, guys.

Tapani. I like the idea of going with TBDs too. I have heard that they can be problematic in snow and ice though. some people say that in very slippery conditions, they can act like an open diff. . You are probably the best guy to ask about this, being from Finland. Do they work well in the slippery stuff, or would a VLSD be a better choice for snow and ice? Also, what did you use to cut the axle shaft from the right rear? ( I saw your posts on that subject) I have access to a horizontal band-saw, a lathe or a cutoff saw, but im concerned about causing too much heat in the axle if I use the cutoff saw. are they soft enough for a band-saw to cut?

Nate, I am aware of the different crossmember mounts and luckily have found the part numbers for the 3 separate pieces, in one of the other threads on the VTD subject. It looks like I can get away with swapping the tail section to the outback trans.'s main body as long as I can get a matching JDM TCU, and have some magic done to its firmware...lol.. Are there also differences in the c-solenoid based on production year too? and, is that c-solenoid typically included in the trans. tail section? or is that mounted in the main trans. body? Im going to have to be sure I get the trans and TCU from the same vehicle if possible, I see. I was hoping to be able to just get the tail section and TCU, but that might prove to be a challenge. wont know for sure until I find a source though..

Thanks again for the responses, guys. It looks like this is going to be a step by step, long term project, considering the costs involved and difficulty in locating and shipping of the parts. If you guys, or anyone else has any further thoughts or advise, Im all ears.....It looks like Im going to start out with a simple 4.44;1 trans swap, for starters, then start collecting the other pieces when I can find and afford them. Im sure more questions and concerns will arise, as they always do.....

Best wishes, from the U.S.'s land of cheese, beer, and bratwurst...
Reply With Quote
  #6  
Old 04-24-2015, 12:40 PM
AirTech90's Avatar
AirTech90 AirTech90 is offline
Registered User
 
Join Date: Mar 2015
Location: Richmond, Illinois
Posts: 14
Registered SVX
Re: New guy needs advise for a 4.44:1 VTD build

OH!...I almost forgot...
Does anybody know if the QC module and/or the "power mod", would be sufficient, to modify the shifting issues with a JDM trans/TCU 4.44:1 gearing? does the weak engagement of our slippery stock shifts and fuel cutout cause the issue with the 4.44 gearing, or is it more involved than that? keeping in mind that Im going to use the stock SVX torque converter too..
And, If it IS more complex than that relatively simple fix. does anyone know who I would have to contact to get those kind of mods done to a TCU?
Reply With Quote
  #7  
Old 04-24-2015, 01:11 PM
Tapani Tapani is offline
Registered User
 
Join Date: Feb 2010
Location: Finland
Posts: 815
Registered SVX
Re: New guy needs advise for a 4.44:1 VTD build

The TBDs are awesome in the snow and on ice. We do ice track days and it's really cool. I have posted photos somewhere....

I ran Truetracs in my offroad Range Rover for 8 years.... and the only time I wished for real lockers were when the axles were crossed so that two wheels had little or no traction at all. Anything times zero will always be zero .-).

I may be biased, but I really like the diffs

I just used an angle grinder to cut the drive shaft. The heat genereted only affects very small distance - and it's not even loaded in this application.

The gear ratio change needs to be taken into account in the TCU firmware. Otherwise the TCU will think the planetary center diff is slipping all the time. The front speed pickup is located at the diff carrier - not the pinion.

The QC and the power mod will not affect this in any way.

Talk to Mike.

Cheers,

/T
Reply With Quote
  #8  
Old 04-27-2015, 05:39 PM
'E''s Avatar
'E' 'E' is offline
Registered User
 
Join Date: Mar 2007
Location: Canberra, Australia
Posts: 430
Re: New guy needs advise for a 4.44:1 VTD build

I have 5 jdm/audm vtd gear boxes and tcu's if you are looking for parts
__________________
92 pearl SVX about to revive
92 Black 4ws (Jap spec) SVX
93 black SVX
93 Liquid Silver SVX - sti 6 speed with R180 diff, my05 sti steering wheel, sti alloy lateral links, 19x8.5 275/30 42mm offset front and 19x8.5 275/30 22mm offset on the rear, 6 pot brembo caliper with 355 rotors front, 2 pot brembos rear
95 bright red SVX
96 emerald pearl SVX about to revive
Reply With Quote
  #9  
Old 04-27-2015, 05:44 PM
'E''s Avatar
'E' 'E' is offline
Registered User
 
Join Date: Mar 2007
Location: Canberra, Australia
Posts: 430
Re: New guy needs advise for a 4.44:1 VTD build

Longassname has done this and has lots of experience with tcu's I think he has the jdm firmware available and modified
__________________
92 pearl SVX about to revive
92 Black 4ws (Jap spec) SVX
93 black SVX
93 Liquid Silver SVX - sti 6 speed with R180 diff, my05 sti steering wheel, sti alloy lateral links, 19x8.5 275/30 42mm offset front and 19x8.5 275/30 22mm offset on the rear, 6 pot brembo caliper with 355 rotors front, 2 pot brembos rear
95 bright red SVX
96 emerald pearl SVX about to revive
Reply With Quote
  #10  
Old 04-29-2015, 07:32 AM
longassname's Avatar
longassname longassname is offline
Just some dude.
 
Join Date: Sep 2002
Location: Miami, FL
Posts: 3,986
Significant Technical Input
Re: New guy needs advise for a 4.44:1 VTD build

I would do it all in one shot if I were you. I would also rebuild the transmission while you are at it. You can probably tackle that yourself, considering. You don't want to put old junk in your car and try to rely on external mods to make it shift better. You can build it right and put something that shifts fast and smooth and you can count on in your car with a little work.

This isn't something I am recommending for everyone but with your experience as an aircraft mechanic I would think it would be a reasonable weekend project for you. You just need to have the right parts up front, have a good amount of clean space to lay your parts out in, and be very organized when you do it.

I can supply you with a parts list. I would suggest just replacing the frictions and steels and not trying to disassemble the pistons to replace the seals. That is several times as much work and beyond a weekend project for a first timer, even a mechanically skilled one.

You can get a vtd from E and I can make your US tcu work with it.
Reply With Quote
  #11  
Old 04-29-2015, 12:27 PM
AirTech90's Avatar
AirTech90 AirTech90 is offline
Registered User
 
Join Date: Mar 2015
Location: Richmond, Illinois
Posts: 14
Registered SVX
Re: New guy needs advise for a 4.44:1 VTD build

Excellent!...thanks for the responses..

Ok...Im gonna have to get my funding together and start crunching dollar numbers before I can start this project. Im in the middle of changing residences at the moment, but Im hoping to start gathering the parts pretty soon, here. Unfortunately, Im not exactly rich, so I may have to work at this for a little while. If I ran out and blew $2500 on TBDs alone, right now, my girlfriend would probably shoot me with my own gun...lol..That being said, I could certainly justify a trans and TCU more easily. Yes, I agree, putting old junk in my car is less than ideal...lol..Ill see if I can get my hands on the factory manuals and give the overhaul a read-thru. Having a clean, undisturbed area isn't a problem, luckily. My supervisor is currently modding the heck out of his Mitsubishi and keeps inviting me to share some hanger floor space, anyways... its just going to take some time to gather all the parts. no worries there, this is why we call them projects...lol..

Just so Im clear in my own mind..is it going to be easier using an existing 4.44:1 gearbox and swap tail sections, or do a swap of the gearing on a complete JDM box?..

E... If you could PM me a price on one of those gearbox and TCU pairs, I would appreciate it. also, if you might have an idea on the price of shipping to the 53148 zip code in Wisconsin USA...

LAN...if you could PM me a cost for the TCU work also, I would very much appreciate that as well. If all the mods to the shift patterns etc. can be done internally, that would certainly be the preferred course. And, yes, if you have a list of parts, that would be great also.

Thanks again, guys...Im looking forward to really pissing off my girlfriend in the near future...lol..

Last edited by AirTech90; 04-29-2015 at 01:22 PM.
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 09:58 PM.


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