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25 spline to 23 pline swap?


Gloyale
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Hey all. My new project i an 84 4wd GL diamond edition sedan. I want to swap in an EJ18 from a FWD impreza I picked up. Initially, I will be doing the engine swap only, using an adapter plate to mate to the 3AT(ugh...I know, I know).

 

Later on however, I want to convert it to AWD 5spd. When I do that, I will be running into the problem of the EA81s 23 spline axles mating to the 25 spline 5spd.

 

So options are

 

1. Cutom axles with EA81 outer CV shaft and 25 spline inner cups(ea82T?Impreza?Legacy?Forrester?)

 

2. swap the 23 spline axle stubs from the 2wd Impreza five speed into the AWD 5spd.

 

Ideas, thoughts, and stuff that's been done?

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I believe I've heard that swapping axle cups is pretty simple....as long as you have 2 pairs of donor axles.

 

swapping stubs is also pretty simple, except the splitting the tranny case part...

 

 

Well. I've heard of swapping the cups from EA82T onto the EA81 axle works. But what about the Impeza/Legacy cups? are the axle shafts the same diameter? spline count? I have an Extra set of turbo axles but they are in good shape, no torn boots, I don't want to tear them down.

 

I was hoping that swapping the stubs could be accomplished without splitting the case. I know that the stubs will just pull right out of my Legacy trans. Held in with spring clips. But that is an Auto. Are the Manuals the same? If they just pull out it would be real easy.

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EA81T cups won't work - wrong shaft diameter, etc.

 

I beilive you are going to want FWD Impreza axles for their inner joint cups. That should yeild the right DOJ to mate a FWD EA81 axle shaft to the 25 spline transmission.

 

I don't think a solution has yet been found for the 4WD EA81 axles.... but with AWD there shouldn't be any trouble running the smaller FWD shafts anyway as long as you get then with new outer joints. Maybe contact this MWE fellow - he might know of a joint to make the 4WD shafts work.

 

I seem to recall something about the EJ22T DOJ's fitting the EA81 4WD shafts....

 

The Legacy stubs might pull out, but there's no replacement in 23 spline that would go back in. The EA stubs are bolted from the inside and can't be removed without splitting the trans.

 

GD

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The Legacy stubs might pull out, but there's no replacement in 23 spline that would go back in.

GD

 

23 spline stubs from 2wd Impreza? that would be perfect since that is the trans in the car already. Those stubs wouldn't match to the AWD trans?

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I would swap the cups on the driveshafts. Splitting the box just for that is a lot of work.. If your putting an LSD in the front, then I would split the box right away!

 

The stub shafts pull directly out of the AWD auto trannys, at least the early Legacy ones.

 

If the 5 speeds are the same way, then it would be easy to pull the 25 spline stub out and use a 23 spline from a 2WD Impreza. Or am I misinformed that 2wd Imps use 23 spline?

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There is a 'small' 25 spline EA-82 turbo DOJ cup that will swap onto a EA-81, of non turbo EA-82 axle. I dont know what they are stock on but I know my RX had one(OEM) and have seen one other at the junkyard. I think that the stub axle swap would be a better choice, that way you could just run stock axles.

 

Matt

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Another idea is to swap in a N/A 5 speed D/R tranny out of an 86-89(i think they made it in 89) GL wagon or 4wd sedan. unless you really want the awd, but i think D/R is better offroad. that way you can use your 23 spline axles you have. of course you wouls have to swap in the D/R tranny, but it might be worth considering.

 

 

~Josh~

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Another idea is to swap in a N/A 5 speed D/R tranny out of an 86-89(i think they made it in 89) GL wagon or 4wd sedan. unless you really want the awd, but i think D/R is better offroad. that way you can use your 23 spline axles you have. of course you wouls have to swap in the D/R tranny, but it might be worth considering.

 

 

~Josh~

 

No, the 84 Black Diamond Sedan is going to be an on-road car. Possibly even Lowering it for improved camber, center of gravity and looks:grin:

 

But definately want the AWD 5spd. I suppose I could use an RX or Fulltime XT trans, but they are harder to find, and older and more abused by the day. Besides, I want to use it with the EJ18 or EJ22 going into it. I could do something more agressive power wise(EJ25,EJ22t,EJ20g)but I want really good gas milage. I want to make it a stylish daily driver. But with a few extra ponies too.

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Allright got a shaft.Heres the combo i used a fwd auto ea 81 shaft, outer cup and the ea81 inner ball race which i slipped on a early ej inner cup not sure which model it came of but its about the same size as the ea one that came of and the ball and race matches. I fit it up to a auto ej front diff[25 spline].

One thing to watch for is ej box maybe slightly wider at the stubs limiting the inward movement at the inner cup.

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stub shafts - they are easy to remove from automatics, but they are not removable from manual trans without splitting the block.

 

if it was in the future anyway, do an XT6 5 lug conversion and then using XT6 axles? if there's any way to do everything at the same time, swapping in the AWD trans now would save you time.

 

for gas mileage - an 88-91 FWD manual XT would have been an awesome starting point. 40+ mpg all highway driving right out of the box and the best hp rating of any non-turbo EA engine you can get.

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stub shafts - they are easy to remove from automatics, but they are not removable from manual trans without splitting the block.

 

if it was in the future anyway, do an XT6 5 lug conversion and then using XT6 axles? if there's any way to do everything at the same time, swapping in the AWD trans now would save you time.

 

Well, that sounds like you are pretty sure about the 5 pd stub shafts. Damn.

 

adly, I don't have an AWD 5spd at the moment either. I jut want to ge thte EJ installed first, using an adapter. I wonder what EJ power will be like through the 3at?

 

As far as a 5 lug conversion from XT6. Firstly, I don't have an xt6 to scavenge. Buying one or all the parts would be spendy too. Second, I am not sure I want to be saddled in the future trying to find XT6 rear discs, pads, bearings, etc. Plus, XT6 axles would be too long for an EA81 as well, so now I'd be mixing and matching 4 axles and not just 2.

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now I'd be mixing and matching 4 axles and not just 2.

 

nope, rear axles, trailing arms, and spindles are the same in a '6. just the hubs, rotors, and backing plates are different. the calipers are the same as any turbo EA82, so pads are easy to find. and the rotors aren't terribly hard to get a hold of.

 

but yes, and XT6 axle will not work with an EA81 control arm.....so you wouldn't have to make any hybrid axles, but you would have to shorten them....

 

5-lug is not a terribly attractive option.

 

and swapping to an AWD 5-speed is a whole new can of worms, so it's not a terrible idea to postpone that.

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Well, that sounds like you are pretty sure about the 5 pd stub shafts. Damn.
yes, i'm positive of that.

 

i haven't found XT6's difficult to come by. i had 9 XT6's on my property last year. i've gotten 4 free and had opportunities for more in the past that i just didn't have a need for, but of course chance is the rule here. one in MD was posted on here by a member in CA and i followed up on it. keep your eyes peeled. saw one in the paper last week and drove past one in a fenced in yard a couple weeks ago, i might stop and see if they want to get rid of it, i have some friends that might drive it.

 

there was a member in Ohio that had a few that he didn't have a need for, but haven't seen him on here in awhile.

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