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Front diff interchangeability: The true answer


WJM
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what would you suggest for my single range 5spd in my xt6.. for general street / mild offroad?

 

is it going to be a real PITA to swap a new front diff into this transmission do you think?

 

sorry for questions, don't have FSM with me at work

 

A 'light' clutch type. Nothing really heady duty. Something like an off the shelf Cusco or Kaaz.

 

And yes, this is one of those things that you would not want to "try at home"....but if you are very good at mechanical stuff and have no problems learning...simply replacing the front diff is easy...but NOT for a faint of heart.

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Next I wanna see what it might take to mount a center diff from an EJxx series car into our EAxx series cars. Can it even be close to possible?

 

That is impossible. :rolleyes:

 

The new style VLSDCD will not work at all, PERIOD.

 

However, the older style VLSDCD is *rumored* to work with minor modifications.

 

*IF* it works using the stock stuff...then I can use it in SP....I am looking for a 1st getn VLSDCD equipped 5spd...its from MY89 to MY93.

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That is impossible. :rolleyes:

 

The new style VLSDCD will not work at all, PERIOD.

 

However, the older style VLSDCD is *rumored* to work with minor modifications.

 

*IF* it works using the stock stuff...then I can use it in SP....I am looking for a 1st getn VLSDCD equipped 5spd...its from MY89 to MY93.

 

so an older Legacy VLSDCD might work? I heard that in the automatics, the AWD was engaged by a solenoid on the tranny. What if you were able to use the center diff from the automatic, hook the solenoid up to a potentiometer and turn it into like a DCCD? Possible?

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Cos I'm a noob and have only worked on EA81's with 4sp boxes, does the EA82 5sp box use different amount of splines on the drive shafts? I thought it was only the turbo EA82 5sp boxes that had that. I might start looking into a 5sp box conversion now :-/ like I even have the money for a rear LSD, little own a front one :-/

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so an older Legacy VLSDCD might work? I heard that in the automatics, the AWD was engaged by a solenoid on the tranny. What if you were able to use the center diff from the automatic, hook the solenoid up to a potentiometer and turn it into like a DCCD? Possible?

 

Thats a good idea...but the casing would need to be redically altered to house it...AND the ATCD parts are designed to function with ATF and not gear oil...so you would need to seal off the 'DCCD' so it uses ATF...then find a way to circulate it and cool it, as the case would be very small and the ATF would heat up very fast under slip conditions.

 

Cos I'm a noob and have only worked on EA81's with 4sp boxes, does the EA82 5sp box use different splines? I thought I was only the turbo EA82 5sp boxes that had that. I might start looking into a 5sp box conversion now :-/ like I even have the money for a rear LSD, little own a front one :-/

 

The 4wd, 4wd turbo, and 2wd turbo all use 25 spline axles and stubs.

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Thats a good idea...but the casing would need to be redically altered to house it...AND the ATCD parts are designed to function with ATF and not gear oil...so you would need to seal off the 'DCCD' so it uses ATF...then find a way to circulate it and cool it, as the case would be very small and the ATF would heat up very fast under slip conditions.

 

Are the internals the same from auto to manual or are they different as far as the center diff is concerned? If possible, what about swapping the internals from the manual center diff into the housing of the automatic, then connecting it with the manual tranny and running gear oil through it? Just doing some theoretical research since I myself have never had any of these trannys apart yet.

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Are the internals the same from auto to manual or are they different as far as the center diff is concerned? If possible, what about swapping the internals from the manual center diff into the housing of the automatic, then connecting it with the manual tranny and running gear oil through it? Just doing some theoretical research since I myself have never had any of these trannys apart yet.

 

No, they are all different. The JDM autos, the NICE ones have a REAL center diff that is like the DCCD units. However, none of that stuff can interchange as far as I know. All of it is different.

 

However, aquire some and try it. I just dont know for sure....but I am betting that it wont work.

 

Ummm...I've used 3AT FWD axles on my d/r 4WD car with no problems (both EA82 N/A)....I think it's just turbo vs. non-turbo

 

Well...I have seen N/A 4wd transmissions with the 25 spline on EA82 cars. I am sure that ALL ER27's have the 25S axles...and I know that ALL EJxxx/EGxxx/EZxxx cars are 25S until they switched to stubbed axles.

 

don't some newer impreza's have limited slip center diff options as well? any chance of those swapping over?

 

ALL EJ/EG/EZ AWD cars have an 'lsd' center. The EARLY 5spds should swap into our FT boxes with little modification. I know the later ones will not, I tried it.

 

Ok.. noobish questions here....

Can I do this to the 2wd turbo 5 speed tranny I have in my 6?

Did/What cars came with something like this stock? Seems too fancy to be stock, but I donno....

 

I would tend to think even the 2wd 5spd 'turbo' transmissions (ones with 25S axles) have the same diff. I need to look up the PN on those transmissions.

 

what came with a front LSD stock? most to al of the later STi's...and most of the 'special' models that we never got. ZERO SUBARUs came with a front LSD here in the USA...except for the STi. You cannot use the 6MT front diff. It is an ENTIRELY different unit...much smaller...it 'fits' but it doenst line up to anything.

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I was talking to my dad about this over christmas dinner... his response was "you have the transmission out of the car already right?..... bring over a differential and I could do that for you in a couple of hours"

 

bearings, shims, tolerances don't seem to bother him.. he is an engineer it's what he does :rolleyes::banana:

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Are the internals the same from auto to manual or are they different as far as the center diff is concerned? If possible, what about swapping the internals from the manual center diff into the housing of the automatic, then connecting it with the manual tranny and running gear oil through it? Just doing some theoretical research since I myself have never had any of these trannys apart yet.

 

Completely different, the auto has permanent FWD and a clutch pack to engage the rear wheels on demand, no differential at all. To convert an auto to have a proper centre diff you need a late auto box, they did away with the clutch system and went to geared diffs.

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