JDM Switchable T-case [Merged 1-8]

[DV8tion]

How can a JDM switchable (FWD/AWD) transfer case work? In FWD mode the VC would just transer most of the power to the (now unhooked) rear drive shaft. I am probably missing something about this. Do the transmissions these transfer cases come with not use VCs?

 

[GRNDSM]

You need to swap in a welded VC or welded center diff to be able to switch into FWD.

Leon
RR

 

[DV8tion]

What about the cars that came with these T-cases? How do they work in FWD mode?

 

[zac83]

the switchables have disable pegs in both the t case and the transmission so that you effictively disable the power flow on both sides of the viscious coupling. if im not mistaken tho, the center dif still spins independant of the VC, tied into the output shaft...

its not just the T-case, its the transmission too...

 

[GRNDSM]

I never actually saw the inside of tranny (just the CAPs drawing of it). It appeared to me that they have a locking feature to their VC, but I am not 100% sure.

It would be nice to build this feature into a DSM tranny .

What I was never able to get an answer to, was how was this supposed to be actuator. One person told me that had to manually unscrew the bolt and switch it. Somehow, I am having a hard time imagining that any car company in 1990 would sell a car with this “feature”. I think that there must have been some sort of a solenoid or a cable. There are provisions for such device on the transfer case casting.

BTW even US spec. transfer cases have all the features for switchable transfer case in the casting of the body (but they are not machined out).

Leon
RR

 

[2-0turbo]

Originally posted by GRNDSM
I never actually saw the inside of tranny (just the CAPs drawing of it). It appeared to me that they have a locking feature to their VC, but I am not 100% sure.

It would be nice to build this feature into a DSM tranny .

What I was never able to get an answer to, was how was this supposed to be actuator. One person told me that had to manually unscrew the bolt and switch it. Somehow, I am having a hard time imagining that any car company in 1990 would sell a car with this “feature”. I think that there must have been some sort of a solenoid or a cable. There are provisions for such device on the transfer case casting.

BTW even US spec. transfer cases have all the features for switchable transfer case in the casting of the body (but they are not machined out).

Leon
RR

What is this CAPS drawing you speak of? You have a copy? How hard would it be to modify your US xfer case to JDM spec? I can machine stuff to make components as needed, but something to guide me to see how they originally intended it to work would be valuable.

 

[GRNDSM]

Dare I say… www.VFAQ.com it is under “JDM FWD/AWD Switchable Tranny”

I remember seeing CAPs drawings from RRE, but now, Tom put them in a really nice VFAQ page.

Looking at his photos, converting US spec tranny to lock the center diff should be doable.

Leon
RR

 

[purplehazetsi]

i just saw the JDM Switchable Transfer case, and i think its a really nice thing to have.. BUT.... were can i get one? i have no clue were too look

 

[Lordpaxin]

Ebay, dsmtrader, or the classifieds,

you do know that to switch it back and forth, you have to crawl under the car, and pull a bolt out of the Xcase right?

 

[purplehazetsi]

Yeah i know that, but do i need a different trans too? or will my stock one accept the Switchable Transfer case

 

[DrZiplok]

You have to have both the switchable transmission and the switchable transfer case.

You could use the transmission by itself (centre lockup), but the transfer case just lets you *disconnect* the rear wheels.

 

[jdbTSi]

Originally posted by DrZiplok
You could use the transmission by itself (centre lockup), but the transfer case just lets you *disconnect* the rear wheels.

So if I have the switchable tranny but a regular transfer case, would it be okay to switch the tranny(4wd to 2wd) and drop the transfer case for dyno purposes?

Could I then remove the driveshaft and drive to the dyno or would it be better to disconnect everything when I get there?

I would assume this would be possible but I just wanted a second opinion. Sorry for the hijack

 

[Sartuche24]

no you need the switchable transfer case because there is a pin that goes from the transfer case and tranny. It won't work without the transfer case plus the transfer case for the switchable tranny is a different gear ratio and i read somewhere the transfer case has to be compatible with the tranny. The tranny and transfer case will bolt right up because they use the same case for the JDM and US model tranny and transfer case, the cases just have a hole machined out for the pin.

 

[jdbTSi]

Well, I have been driving around for the last 3 years with a switchable tranny and regular T-case. I believe any 22 spline T-case will work fine with the switchable tranny. Just for the record, T-case and driveshaft were dropped for the dyno and the car drives fine. (Well if you consider FWD fine...eeew

 

[g9s0x]

i just picked up a switchable transfer case but do not have the switchable tranny. it will do nothing for me to switch the transfer case to 2wd since i do not have the switchable tranny correct? oh well, at least it is all aluminum and saves me a few pounds. maybe i can find a switchable tranny at a local jdm engine importer for cheap. thanks for the help.

 

[wishihadatalon]

is it a bolt that is involved or is it a pin. also is there any way you could make linkage to get it to switch like if you were at a stop sign or something?

 

[Omega]

is it a bolt that is involved or is it a pin. also is there any way you could make linkage to get it to switch like if you were at a stop sign or something?

I would think a heavy duty solonoid.. or perhaps a slave cylinder with some sort of hydrolic actuator could work. It depends on what exactly this bolt/pin does. I get the impression it is the equivilant of a shear pin in a snow blower. It just disconnects the input shaft from the center diff.

 

[bOOstd GSX]

Is it strong? Could it be built up like any other tranny? I wouldnt wanna push 650 hp and the tranny explode cuz it isn't as strong as a regular 5 speed.

TurboAWD92GSX is it still available? Is that for the tranny and T-case?

How sick would that be to have it switchable from inside the car? Pull up next to an STI, smoke the front meats, switch it to AWD and rip him a new one? Ahhhhh, what a day that would be.

 

[GRNDSM]

I believe that it is stronger than the US spec transfer case. But you can brake it...

I am working on a heavy duty cable actuator system. I want to be able to do a FWD burnout to warm up my front tires. Stay tuned...

Leon
RR

 

[z3ds]

I've searched the forum and didn't find the exact info i need. thanks in advance.

I just aquired a 1990 galant gsx. I believe it shares the same drivetrain with the 1990 eclipse gsx. My question is, can i remove/disengage something so it will just run its front wheels ? The reason why i want to do this is to gain some mpg.

(less driveline lost = better mpg) I know the AWD weight will still be there.

correct me if my theory won't work

 

[Thomas91169]

no but i heard there is a pin that you remove and put in another hole to make it RWD.

 

[scotthidley]

1. This wouldn't be worth doing

2. It can be done, but not as simply as stated above. You first need to lock the center diff, either with a viscous coupling eliminator, and / or with a welded diff. Then you can pull the transfer case, and driveshaft. This method would allow a minor mileage improvement, then again, you might not notice a gain, as you'd still have the friction of the rear end.

The other way, is if you have a switchable trans (some jdm trannies have this). Then you'd pull a bolt, which would lock the center diff, then you'd have to pull a bolt on a matching transfer case, to disengage the output shaft. I did this for my way home from the shoot out last year as I snapped the output shaft of the tcase. Anything in 1st or 2nd, of just tapping the gas resulted in wheel spin. The only good thing is I didn't have to turn the steering wheel to pass cars, I just had to signal.

 

[Defiant]

http://www.vfaq.com/mods/Tranny-switchable.html

 

[Morphius]

Galant GSX has a W5M31 trans. The T/E/L DSM's run the W5M33 trans. They are similiar but they do have thier differences like the FWD versions, F5M33 vs F5M31 or F5M22.

The differences are: gear ratios, bellhousings, and most importantly, bearings. The M33 series has tapered bearings to battle the increased torque output of the turbo engines. The M31 has the typical roller bearings.

Bottom line, your trans isn't switchable and is unique to the GSX due to gearing. Change the rear diff and you could go to a JDM switchable type as those above has discussed.

 

[mitsufrkr]

i bought anouther trans & trasfercase. it's switchable from 4wd to 2wd. i was wondering what bolt do i have to move to switch from 4wd to 2wd? thanks in advance