Front diff interchangeability: The true answer

[Kostamojen]

As promised, an EJ diff compaired to a 4-speed diff:

 

 

Did any other manufacturers use the 4-speed front differential? Honda/Toyota/etc.? Maybe one of them did and someone made an aftermarket LSD for it...

[JWX]

wow thats tiny....

[MilesFox]

i read thru to page 14 but there was a brief mention about center diffs. so that prompts me to question:

 

will the vlsd from a 95 legacy type transmission swap in place of the RX full time 4wd 5swpd d/r center diff to make it true AWD with lo range?

 

and if so, can the original diff lock be made to work with a legacy vlsd center?

 

and with that having lds rear, put in lsd front, 5 lugs, an EJ18 with ea82 turbo pistons and wrx turbo.........oops i started to dream

[PoorManzImpreza]

couple things.. here's the formula:

 

true AWD rx gear box:

rx input and output shafts complete

 

remove front diff and pinion shaft from rx box

 

remove front diff and pinion shaft from turbo legacy box

 

reuse legacy roller beearings on legacy pinion shaft including torington bearings and all spacers and the spline adapter. Get new pinion nut and washer..(ok yeah I know I wouldn't either but I gotta say it..)

 

install them in rx output shaft torque nut to 88.5 lbft

 

install turbo legacy front diff in left half of rx box

 

You may have to remove rx input shaft and install turbo legacy shifter forks..

 

install rx/turbo legacy hybrid pinion/output shaft assembly into left half of rx gearbox

 

setup pinion shaft/front diff. tooth engagement

 

tighten flange of four bolt bearing finger tight

 

install right hand side of gearbox case

 

fasten all fasteners to spec torque

 

figure out how your gonna operate the dual range..I recomend utilizing the center diff lock switch..

 

carefully lay a new gasket and install turbo Legacy transfer/center diff housing to rx box

 

acquire turbo legacy and xt6 gearbox crossmember combine them and install to rx/turbo legacy hybrid gearbox..

 

install in car and measure up how much u need to hack off of your ea82 drivershaft

 

install everything..congrats you now have a true awd hybrid rx/turbo legacy dual/range gearbox..

 

oh install turbo legacy rear diff into car

 

I've seen some of this done myself and done some of it as well but I haven't done it front to back so I'm sure many steps are missing..you lose the diff lock..sorry can't be avoided..

some of this was done with a normal dual range and an impreza gearbox..so everything in the impreza box was swapped into the ea82 box..a lil bit different..

regards,

Kaz

 

oh and ea82 turbo pistons are bigger than ej18 pistons so no go..

[Phizinza]

I would read the above post, but its too long and I can answer with a simple no to the RX EJ interchangeable center diff.

They are quite different. You can however put the RX rear gearbox casing with center diff on a EJ gearbox (you also need the pinion shaft and crown wheel) or a EJ center diff with rear casing on a EA82 gearbox (thats right, even the PT boxes). Just screws with your mounts and propshaft length.

[MilesFox]

ok i got lost there between both replies. so if oyu puyt the ej rear diff and casing on the rx tranny is there still a dual range or not?

[Phizinza]

You don't need an RX trans. Just get a PT4WD 5sp. Then get a pre 94 EJ box. Take out the lower gearset from the PT and take out the diff. This is after you've removed the rear casing and 4wd gear. Then put the lower gear set, pinion, diff and rear casing plus center diff in the casing of the PT box. Use the EJ 5th gear and all the other gears 'should' line up right. (I D/R EJ box used the same gear ratios as the FT4WD I had.)

You now have 1.59 to 1 low with center VLSD in a 5sp with the ability to put a WRX front LSD and harder pack center VLSD in. And it will bolt to a EA engine.

 

My gearbox is a EJ D/R front casing with EA82 low range and RX center diff with lock. But its all pretty much just lego. Some parts just don't fit "in" others. So thats why you need the casing and lower gearset.

[Numbchux]

ok i got lost there between both replies. so if oyu puyt the ej rear diff and casing on the rx tranny is there still a dual range or not?

 

yes, but no diff lock.

 

 

a local guy seems to think that a Mazda 323 GTX locking center LSD can be swapped into an RX case with little modification......although neither of us have actually tried it (he's got all the parts....but no motivation...)

[Phizinza]

(he's got all the parts....but no motivation...)

Sounds like me.....

[MilesFox]

ok that is more the answer i sas looking for. because i already have an rx with its driveline, and a junk 95 legacy transmission with a bad gearset(5th should be ok) and the differentials are still good.

 

as far as the ej18 stuff isnt it a 92mm bore like the ea82? i'll have to start another thread for this.

 

and for that notion it would make more sense to build the rx gears up with lo range into the ej transmission case.

 

the donor car i have my legacy trans received a 93 trans in it's place, ans so far it looks the 95 and 93 casings are identical externally.

[Phizinza]

make more sense to build the rx gears up with lo range into the ej transmission case.

Going more offtopic here, but.

You'll need a D/R EJ case, can get those in Australia or New Zealand.

 

I'm not sure if the complete gearset from the RX will work with the front pinion shaft from an EJ (which you need if you want to run a EJ center diff). You see the front pinion shaft goes through the output gearset. If the RX uses different diameter to the EJ in this part it won't just interchange. You'll need the output gearset from the trans your using the center diff out of. If the 1st to 4th plus reverse ratios line up with an EA82 PT box, then you can just stick the EJ stuff in the EA82 D/R casing or RX D/R casing. If the ratios don't, then you'll need the input gearset shaft from an EJ D/R.

I used RX gearset with RX diff and EA82 low range in a EJ D/R casing.

 

It is quite simple, yet hard to explain in text or to someone who doesn't quite know what everything all does in the box.

[joostvdw]

europe also got DR EJ trannies, just FYI

[PoorManzImpreza]

Going more offtopic here, but.

You'll need a D/R EJ case, can get those in Australia or New Zealand.

 

I'm not sure if the complete gearset from the RX will work with the front pinion shaft from an EJ (which you need if you want to run a EJ center diff). You see the front pinion shaft goes through the output gearset. If the RX uses different diameter to the EJ in this part it won't just interchange. You'll need the output gearset from the trans your using the center diff out of. If the 1st to 4th plus reverse ratios line up with an EA82 PT box, then you can just stick the EJ stuff in the EA82 D/R casing or RX D/R casing. If the ratios don't, then you'll need the input gearset shaft from an EJ D/R.

I used RX gearset with RX diff and EA82 low range in a EJ D/R casing.

 

It is quite simple, yet hard to explain in text or to someone who doesn't quite know what everything all does in the box.

 

The output shaft and pinion shaft of full-time ea boxes and awd 5 speed boxes share the same bearings:

8063 42010 and 8063 42020; output shaft/pinion shaft assembly bearings, and 8064 30030, 8065 33010, 8064 25070; these support the pinion shaft inside the ouput shaft..

The one that galvanizes how compatible early (90-94ish) are with ea full time boxes is output shaft part number: 32229 AA000 this is shared between ea fulltime boxes and '90 ej legacy boxes, after 90 1st gear size was altered and required very slight modifications to output shaft...

 

Later model ej boxes still use the same main support bearings, 8063 42010 and 8063 42020 (this supercedes to 8063 42040, btw), but things have been beefed up a little bit, but this doesn't prevent us from sliding a newer ej pinion shaft into the rx output shaft assembly and using the later model transfer case on our ea fulltime boxes...fyi tranfer case gasket on ea boxes is 32145AA001 and 32145AA020 which both supercede to 32145AA030 which is the current p/n for all ej five speeds..

 

Enjoy the lego!

 

Kaz

[Phizinza]

Thanks for that info Kaz. I'll try and remember that for future reference.

[ThirdEyeHatch]

Ok I just read all 17 pages and need some clarification. I have a EA82 D/R 5spd, to put in a aftermarket limited slip I need a carrier out of a legacy with the EJ22. Then put EJ carrier in my EA82 tranny with my ring gear and the aftermarket limited slip?

[coxy]

Ok I just read all 17 pages and need some clarification. I have a EA82 D/R 5spd, to put in a aftermarket limited slip I need a carrier out of a legacy with the EJ22. Then put EJ carrier in my EA82 tranny with my ring gear and the aftermarket limited slip?

 

No the lsd is the carrier and they interchange between any of the five speeds mentioned,so all you need is the lsd carrier assembly.

Unfortunately some have glossed over setting up a differential correctly,what is listed in the factory service manuals is only a starting point,this is the difference between being a well trained factory master technician and a mechanic with similar qualifications from many manufacturers a piece of paper does not give you thirty five years of real world experience.

In no way am I knocking the original poster who has gone to some trouble to help us all, but there are many things he will learn as he goes,I will now pass on some of that knowledge for everyones benefit when setting up any hypoid type differential one of the things that needs to be taken into account is horsepower and use,this will affect just how you set up the pinion depth for instance.

With big horsepower the pinion needs to be set up deeper in mesh with the crown wheel,the reason being that the horsepower will tend to drive the pinion out of mesh so you want it meshing correctly when under maximum load this will particularly apply for a big power EJ Turbo motor.

For an EA motor where power isn't as great it is safe to run purely to factory specs,but in all instances you will need a pinion preload tension wrench and also check the preload on the carrier bearings without the ring gear fitted to get an accurate figure so dummy assembling can take place up to a dozen times or more doing the measuring and changing shims to set preload's,once you have worked out the shim stack for the required preload it then needs to be swapped around to move the crown wheel into mesh correctly,once you have the preload you just move shims side to side to move the crown wheel adding to one side whilst taking from the other but always maintaining the number and sizing of shims overall to maintain preload as previously measured.

You will also require machinist;s marking blue in a tube to smear over the teeth to look at the mesh pattern,the pattern to look for will vary depending on the horsepower,weight of the vehicle and the intended use it is not as easy as some make it out to be if you want reliability for the long term.

As for my expertise in making these statements something you can check out regarding putting money where my mouth is .

January 2009 fourstrokeassociation Fourstroke Wars Imperial dunes Glamis Ca.

TRF-Explosive Racing results speak for themselves Yamaha raptor 804cc Turbo cheers from the engine builder.

[ThirdEyeHatch]

I was looking to put a aftermarket limited slip in. So it will go right into my carrier?

[JordanR693]

So after reading all 17 pages im still a little lost... Im wanting to take the front diff or carrier out of my 94 impreza L 1.8 FT AWD 5MT and put it into a E82 DR 5MT Non Turbo Trans. I have an experienced mechanic friend to help me my question is can it be done. I know the subject has been torn through with a fine toothed comb but im still a little confused. Thanks

[edrach]

Not having read all 17 pages, but I did read where "final drive ratio was not a concern."

 

I can't speak to EA gearboxes, but I do know that the EJ gearboxes came with a 3.900 or 4.111 ratio (check out the transmission charts in the USRM). If you're just adding an LSD that shouldn't change anything, but if you're changing the gearbox, make sure the front diff and rear diff ratios are the same.

[JordanR693]

What im geting at is im looking to take the trans out of my impreza to swap the dr trans. Im just looking to take the open diff out of my >US Impreza (AWD) MY94TY752VX3CA3.5451.9471.3660.9720.780N/A3.4161.0004.111Viscous (4kgf)Open

and put it in my E82 DR 5MT. Can that be done?

[idosubaru]

Here you say you want to take out your imp trans and put in the DR trans.

im looking to take the trans out of my impreza to swap the dr trans.

 

then here you say you want to take the open diff out of your imp trans and put it (the open diff?) in your DR trans:

 

looking to take the open diff out of my >US Impreza (AWD) MY94TY752VX3CA3.5451.9471.3660.9720.780N/A3.4161.0004.111Viscous (4kgf)Open

and put it in my E82 DR 5MT

 

What exactly are you trying to do? We can't hear, see, or touch anything - descriptions are important for us to help online.

 

I'm guessing you're wanting put the DR guts into the imp trans? If that's the case, there's some other threads you need to read. I'm forgetting details but that's been talked about and I think you'll find some really useful stuff in those threads. I'm thinking Gloyale recently had some dealings with this.

 

The wisest option is to get an EJ to EA adapter and just run the EA trans in your vehicle. You might just run into axle issues since your trans is from a non-turbo and will have the wrong spline count I think. But that's not hard to remedy, i think you just use 1993 FWD impreza axles.

[JordanR693]

I've got all the adapters and what not to make this swap work... What im trying to figure out is if i can take the diff out of my imprezas single range transmission and put it into my e82 dual range transmission before i put the D/R trans in my car. That way i dont have to change anything in the rear diff and i retain my stock 4.11 final drive.

[idosubaru]

Cool, awesome. Someone just posted about doing something...but i can't remember what it was - with a DR and after only a few thousand miles and couple months it grenaded. He thought it was due to the teeth cut being different even though everything appeared to line up and work.

 

That's from memory though, I'm not sure if it was front diff, ring, pinion, whatever you'd want to find that thread - just in the past couple weeks - search for Gloyale as the starter of the thread under advanced search, i think it was him.

[Phizinza]

You cannot run 4.11 or 4.44 gearing in an EA82 gearbox without expensive precision cutting and welding of pinion gears. This is because the EJ gearbox has a pinion shaft running through the gear shaft while the EA gearbox has the pinion gear on the end of the gear shaft. Unless you have a FT4WD, which is the same as the EJ in that it has a pinion shaft running through the gear shaft but because the pinion shaft is different you cannot swap them around anyhow.

 

It might be possible to run the EA82 dual range box modded to the EJ centre diff casing and running a 4.11 with a 1.59 low range like someone on here tried recently but at the moment it looks like what gray said is the problem and you'll just get a grenade of the gearbox problem.

[JordanR693]

It might be possible to run the EA82 dual range box modded to the EJ centre diff casing and running a 4.11 with a 1.59 low range like someone on here tried recently but at the moment it looks like what gray said is the problem and you'll just get a grenade of the gearbox problem.

 

Can you get an adapter plate to mount the e82 box to the center diff of the EJ trans or is there other means of going about it? Who has tryed this is there an old post on this topic?