Gearbox stubs into rear diff

AndrewT · Post by **AndrewT** » Sun Mar 22, 2009 2:26 pm

Take the stub axels out of a 5spd parttime gearbox and put them into a rear diff.

The object of this excercise is to have a rear diff with 25spline stubs instead of the usual 23spline items. Obviously I will need a donor gearbox which has the 25spline stubs.

Does anybody know if this is possible? Are the stubs the same?

Phizinza · Post by **Phizinza** » Sun Mar 22, 2009 3:27 pm

I know the diffs are completely different... Also the front stubs are held in with circlips while the rear ones with E10 Torx bolts.

AndrewT · Post by **AndrewT** » Sun Mar 22, 2009 4:40 pm

No worries, sounds like it's gonna be easier for me to get 23spline front inner CV cups instead then.

nncoolg · Post by **nncoolg** » Sun Mar 22, 2009 5:48 pm

What for are you doing this?

Phizinza · Post by **Phizinza** » Sun Mar 22, 2009 5:56 pm

I think he wants to put a rear diff up front...

nncoolg · Post by **nncoolg** » Sun Mar 22, 2009 5:58 pm

why? cheap LSD center?

AndrewT · Post by **AndrewT** » Sun Mar 22, 2009 7:35 pm

yeah, this is for possible future transfer case conversion. I would mount a rear diff up front of the car and use that to drive the front wheels instead of the front diff in the gearbox - this would go unused.
Yes I would likely run a clutch LSD diff up front then.

nncoolg · Post by **nncoolg** » Sun Mar 22, 2009 7:38 pm

As in have a part time 4wd that uses rear wheels all the time, then selects front wheels upon engaging? A-LA-big fourbi?

AndrewT · Post by **AndrewT** » Sun Mar 22, 2009 10:03 pm

yeah, I plan to weld the centre of an RS turbo AWD gearbox and remove it's front diff to convert it to RWD only.
Then fit a transfer case from a big 4x4 behind it. The transfer case will drive my standard rear diff at the rear, and another rear diff I will mount backwards at the front of the car.
Selectable as 4x4-hi, 4x4-low and RWD-hi.
Probably gonna use a Suzuki Vitara transfer case but still undecided.

YouTube · Post by **El_Freddo** » Sun Mar 22, 2009 10:11 pm

Makes sense now! Problem is as Phiz said - the torx bolt system to retain the stub axle in the rear diff, then you gotta look at the shape - I don't know if they differ between front and rear.

I think the easier option would be to run the carbie driveshafts up front, that way you'll have 23 spline all round...

If you use an EJ dual range with the L series low range installed + a dual range transfer case out the back of the gearbox, you would have:

4x4 hi/hi
4x4 hi/low
4x4 low/low - should be a good crawler gear or bring to back to almost normal L series low
2x4 low/hi (why you'd use this I don't know)
2x4 hi/hi (everyday use)

Cheers

Bennie

AndrewT · Post by **AndrewT** » Mon Mar 23, 2009 8:23 am

Yeah I could do that but too much trouble and don't really need the double low range. Too much trouble to make a EJ gearbox with L low range - my existing EJ dual range isn't suitable for that being a later model Outback one, only option is getting a custom gearset which is expensive. I'd have to source an early Lib dual range box and put 1.5low into that. For now I'd prefer running a proper turbo gearbox with pull clutch to match the EJ20turbo engine. Getting an old RS turbo gearbox welded to be RWD is easy.

Point · Post by **Point** » Mon Mar 23, 2009 8:38 am

is there a reason not to change the whole gearbox? The Subaru 'box is a known weak link, and you're not going to use the front drive, so why not put in for example a celica/supra box? chances are you could even get a toyota transfer case to bolt on the end of it too....

AndrewT · Post by **AndrewT** » Mon Mar 23, 2009 9:43 am

I'm going to be using a divorced transfer case, not one that bolts directly to the gearbox - it will be linked with a simple short tailshaft.
I'm not expecting a EJ20turbo gearbox bolted to an bog standard EJ20turbo engine to be a weak link, especially with me at the wheel - it's not exactly going to be getting rev limiter launches etc. Personally I've never had a Subaru gearbox fail on me at all.
I want to use a Subaru gearbox in this case for simplicity. I will be using a totally stock standard clutch, and it will bolt up without the requirement for any adaptor plates etc.
I did have ideas about adapting a 4x4 gearbox and matching transfer both from a donor "big 4x4" but the method I've arrived at seems alot easier and I think it should be okay. Kindof unexplorered territry tho so I guess I will find out if changes need to be made!

Well, plenty of guys in the US on the USMB forum have put transfer cases in L series...but as far as I can tell they are all just using the original EA82 engines and gearboxes - they just put the gearbox in 4x4 mode and leave the front driveshafts off. With my engine I'm not happy with using an EA82 gearbox.

discopotato03 · Post by **discopotato03** » Tue Mar 24, 2009 1:32 am

I'm curious to know where there would be space to hang the front R160 and how to get the driveshaft under the middle to drive it .

Um also your going to find that those rear shaft joints are not designed to take the scope of movement that the steering will require .

Interesting project though .

vincentvega · Post by **vincentvega** » Tue Mar 24, 2009 7:59 am

read his signature - 6" lift kit

the front diff thing has been done plenty of times in the states. the shafts obviously work

AndrewT · Post by **AndrewT** » Tue Mar 24, 2009 8:28 am

Yeah, 6" lift - trust me there is a cavernous amount of room under my car. The front shafts are going to be every day normal RS turbo front driveshafts as they are right now, but I will just have to work out how to get 23spline inner cups onto them to suit the 23spline stubs on the R160. Obviously I won't use rear shaft joints, 23spline front joints are not scarce! (almost every L series has them). Shouldn't be too hard, I'll likely give that job to my local CV/driveshaft place to arrange.

Phizinza · Post by **Phizinza** » Tue Mar 24, 2009 10:10 am

ahh, I like this little world of subaru here on AUSubaru, people don't seem to get out and look what's been going on else where so big lifts and t-case mods seem so amazing.

discopotato03 · Post by **discopotato03** » Tue Mar 24, 2009 11:02 am

Nope , when you see 4WD trucks (12 tonners) getting their chassis cut in half to accept bogie drive rear sections uni body changes are not so shocking .
Correct me if i'm wrong but haven't people had live axles under MY/L's at USMB ?

Really Lives make it easy because the diff is supported by the axles and housing and the whole lot hangs off the suspension location points .
The axle housings obviously have swivels and internal joints for steering .

A LOT of work but is there any full chassis 4WD type basis you could throw your body over , thats been done before with some success .
Provided you could find something with a similar track and wheelbase it could work . The short ~ 2.5 cylinders long engine bay could be a challenge if you wanted to run an inline 4 in it .

Who knows , maybe a very early shorty Hilux chassis may go under an MY or L .

A .

AndrewT · Post by **AndrewT** » Tue Mar 24, 2009 12:09 pm

Yer - My job here really isn't that exciting, certainly not full chassis like that. I'm still going to think of my car as a Subaru as it will still retain Subaru suspension, hubs, brakes, driveshafts, gearbox, diffs, engine etc etc. Only foreign thing I'm really introducing now is a transfer case, probably from a Suzuki...oh well it starts with S. If Subaru made one I'd use it

daza · Post by **daza** » Tue Mar 24, 2009 3:44 pm

The reason these sort of mods don't interest me is thay are not registerable.
I've no interest in towing my offroader around.
Daza.