AWD D/R (Manual) Gearbox with a center locker?

[ellie-ray]

Hey all,

I'm looking to upgrade the running gear in my L series (Loyale).

I'm just wondering if anyone knows a way to have an AWD manual dual range gearbox with a center differential locker. From what I understand all manual EJ gearboxes have a viscous center diff. I know there is automatics that you can do the "center locker mod" to although would much prefer a manual not only for the reliability and other advantages a manual box offers but also because I intend to get custom gears cut of the lowest low range possible considering the area constraints of the gearbox housing. However if it has to be an auto then so be it.

In my searching I did find this by the master of gearboxes; Phizina. Although I'm not too sure how I'd go finding a FT4WD box in Australia or getting one to here https://offroadingsubarus.com/subaru-tri-hybrid-ft4wd-transmission-centre-locking-differential/

Thanks in advance.

Edited June 6, 2020 by ellie-ray

[dfoyl]

Bennie is the gearbox master here for what you are looking for. You need an early EJ box and your L-series, plus Bennie-level skills to put it together.

[el_freddo]

Hehehe... thanks Dean! I don’t see it like that, I’ve have my gearbox opened up and played with more than I’d like to admit. 

For those playing in the northern hemisphere, this info involving dual range EJ gearboxes is specific to the Australian market - we didn’t get cool models like the RXII coupe, but we did get the EJ dual range AWD box for many years across the EJ range (minus turbo models as they’re all single range).

Now, pack a lunch - you were warned  

@ellie-ray - I too was started with help from Phinzina’s information. Those gearboxes do exist in Australia - but they’ll be tucked under a bench or in a forgotten L series/Vortex that someone doesn’t want to or doesn’t care to sell on to someone like yourself. And you need to be careful not to get one with a flogged out centre diff - they’re rarer than finding rocking horse shite AND hen’s teeth!! You have to find them in a complete gearbox.

You don’t need to cut the best low range gears possible, but that would be fun to do for a lower low range. Just use the L series NA low range gear set that gives you 1.59:1 low range. The next issue is diff ratio as this is commonly over looked in the earlier Subaru’s due to lack of factory options and the complexity of this mod. 

The L series AWD locking centre diff box came in 3.9 and 3.7 diff ratios with dual range and single range, the dual range had the crappest low range of 1.19:1 (at least it was an option!), but you can still build a dual range locking box from a single range AWD locking unit with a phase 1 dual range EJ AWD box - and use it behind an EA or an EJ engine.

How you go about this swings off what engine you’ll be running - the EA82 or an EJ engine. This will determine which gearbox front cases you’ll be running with. 

 If going EA, you need to ensure you have the spring and dedent ball setup for the low range selector fork, this requires mods on the selector fork to mimic that of the EJ selector fork (at least I think you do as I’ve not done this setup before), and the EA cases will need to be modified for this as well. 

The low range swap is basically the same as the one swapping the L series 1.59:1 into the EJ case - again, how closely you follow this depends on what you build it into - the EA cases or the EJ cases (early EJ dual range cases uses same input bearing and housing as the EA82 dual range). The low range hub will need to be machined for the EJ gear set mounting regardless:

https://ausubaru.com.au/viewtopic.php?f=22&t=13511 

The EJ phase 1 dual range gear sets are important only if you’re converting a single range AWD locking box to dual range in the EA front cases. You use the EJ dual range gear sets with the locking centre diff, matching housing and the matching ring and pinion gears in the dual range EA front cases. You’ll want the L series 1.59:1 low range too - NA PT4wd is where to find this. Also choose your diff stub spline count - 23 (EA82 carb) or 25 (EA82 MPFI, turbo and EJ AWD). The L series has front shafts for both output stub axles from the factory.

If you’re going for an EJ engine, I’d recommend the above but with a phase 2 EJ AWD dual range - first gear is stronger, the cases are stronger and *generally* they’ll have less kms than the earlier phase 1 boxes. Look for one from a 2002 onwards as I’ve come across two ‘99/‘00 gearboxes with phase 2 beefier cases but still retaining the smaller first gear with the lower strength. Both of these phase 2 gearboxes had diff output stubs from factory - I’m yet to confirm if this is the indicator of the difference. Also use the EJ flywheel and clutch. The phase 2 boxes use a hydraulic clutch setup, swap the fork for a cable operated fork (you’ll need the clutch cable stay bracket too) from the phase 1 box, and use a solid flywheel from the same - it all bolts up and works easy. You just have to swap the pivot bolt for the clutch fork to the lower mounting position.

With that said about the beefier first gear, I blew second gear in my original AWD locking box build (EA AWD gearsets) - before I got it someone mated a single range lower gear set with a dual range upper gear set for the low range. This is a no-no with mix and matching gear sets and things can eventually go bang as an end result. I didn’t overload the gear, it became difficult to select on my way out bush, I didn’t think anything of it and rev matching made it all work fine. Down shifting as I was slowing and going uphill saw it let go, no over revving or anything, an easy load and it unleashed 1000 leprechauns with hammers inside my gearbox!

Diff ratios: only way to swap unless you have the matching set is a cut and shut job from a reputable company that is willing to do the job (or you’re a really good machinist and welder). The pinion shaft in the locking box is unique in that it’s the longest produced by subaru, and thus IS NOT interchangeable with other EJ AWD pinion shafts. There’s a spacer tube in the pinion shaft system that’s critical to get the pinion shaft length bang on the same as the original pinion shaft before mods. I spent 4 hours hand filing that hardened sucker down to allow proper preload on the lateral bearing(s), I cant remember if there was one or two of these bearings in there.

If you want 4.111:1 or 4.44:1 you will need the cut and shut method, and if running the 1.59:1 low range, the ring gear on the diff needs to be shaved to clear the low range gears. It gets out of hand quickly! 

While you’ve got the whole thing open, drop a front LSD in there. I used an OBX helical unit from the states. If you go this way, use the rebuild kit before installing it for best performance and longevity - this is something I hope to do with my front LSD at some point as it’s not working as effectively as it did when new. The bolt heads on the LSD needed to be shaved to clear the low range too! All works well though. 

So here’s my setup: phase 2 EJ dual range front cases and matching gear sets from an SG forester, L series 1.59:1 low range with auxiliary oil feeders over the low range gears, OBX front LSD, 4.111:1 diff ratio using a custom pinion shaft with the L series AWD locking centre diff, running 27 inch diametre tyres. An EJ22 does all the work out front.

I’d go 4.44:1 diff ratio (and the lowest 5th gear ratio) if I had my time again with the custom pinion shaft. 

If I break that centre diff, this gearbox build is essentially toast as replacement centre diffs are none existent. 

The whole point of this build for me was to have awesome daily driving manners and off-road ability. AWD in the L series is mint to say the least. Fuel usage does go up a little though, it’s now hard to pull under 10L/100km but that could be due to other mods too - lift, tyres, dual battery, fridge, recovery gear and roof racks, engine age and wear (I’ve put it through quite a bit). It all adds up! 

The other good thing about this mod is that your tail shaft, gear selector linkages and gearbox crossmember all remain factory in the L series. 

After reading that and you still have questions, fire away! 

Cheers 

Bennie

PS: this is probably my longest post on this forum!

[ellie-ray]

Thanks so much Benny. I wasn't expecting such a comprehensive reply. I used to watch you guys with all your amazing projects over at ausubaru with serious admiration ~10 years ago when I was youngster. Unfortunately once I finally had the money to start properly doing up my cars I had an extremely serious turn of health not long after making my intro post there and crashing my lifted L series. Had to sell all my cars and was for many years subiless . Fast forward to now and I have my health back (mostly), have graduated uni and have a brilliant job so am ready to live my dreams (OK enough fanboying ).

I know the 1.59:1 is quite decent, I just think something a bit lower would really take these cars to the next level.

My general plan for the car (L series Touring Wagon) is either an EJ22 or EJ20T engine, with an AWD D/R gearbox w/ center locker with a 4.44 ratio (now I know I can do so!) and the r160 diff so I can run a torqlocker in the rear. I want something that I can regularly drive which also has great offroad capability to take me to some of the most remote places in Australia.

I don't think I fully understand this bit though. I would probably need to see it with my own eyes to fully grasp it.

23 hours ago, el_freddo said:

Diff ratios: only way to swap unless you have the matching set is a cut and shut job from a reputable company that is willing to do the job (or you’re a really good machinist and welder). The pinion shaft in the locking box is unique in that it’s the longest produced by subaru, and thus IS NOT interchangeable with other EJ AWD pinion shafts. There’s a spacer tube in the pinion shaft system that’s critical to get the pinion shaft length bang on the same as the original pinion shaft before mods. I spent 4 hours hand filing that hardened sucker down to allow proper preload on the lateral bearing(s), I cant remember if there was one or two of these bearings in there. 

Firstly, is there any companies you'd recommend for the cut and shut on the pinion shaft as I have no real machining skills whatsoever. Although I do have a friend back in QLD who is a fitter and turner and owns a nice lathe. Also, did you have to file it down even after the cut and shut job?

Also, how did you put the auxillary oil feeders in for the low range? This would be brilliant to ensure the low range gears maintains lubrication on steep angles.

Otherwise, I guess it's time to start gathering the parts for this build so I can get started. I think I'll look into importing an EA AWD box from the states and then go from there.

Thanks again for the excellent info mate.

[el_freddo]

No worries Ellie-ray. 

Low range oil feeders on this page. Pics will tell you more with way less words! 

https://ausubaru.com.au/viewtopic.php?f=72&t=11733&start=555 

The EA AWD pinion shaft is LONG, probably close to 60cm from memory. The EJ pinion shaft is closer to the 40cm mark. 

So you need to “cut” the gear off both shafts and weld the gear ratio you want on to the EA’s pinion shaft. 

I say “cut” as it’s much more involved than that. When I snapped my first pinion shaft weld job (someone did a massive dodgy on it, less than 2mm penetration around the circumference), I was “lucky” enough to be in the company of a good mate in WA that had a network of mates that knew someone that could do something I couldn’t do. So I got to watch the process of the cut and shut which is much more involved than is sounds. 

Basically each piece was shaved at the point determined as the strongest and not at a bearing position - from memory about 70mm from the back of the pinion gear head. One piece was made with a make stub and the other with as a female, both mating edges were beveled. These were then pressed together and the now beveled valley welded in. Once this was checked out on the large and was generally “true” (the shaft had a twist in it and the lathe a 0.004mm movement), a capping weld was done and this was shaved flat in the lathe. 

If the weld colour was the same, you would need an X-ray to know what was done. 

As for who to go through, I don’t know, you’ll have to investigate that. 

The tube that I shaved down is the spacer tube that the centre diff sits over. Because of a slight change in length of the pinion shaft, when the pinion shaft end nut was torqued up to spec I could not freely rotate the lower gear sets, or the pinion shaft independently of these. Shaving that tube down allowed this to occur as the lateral bearing(s) were no longer squashed. 

Best of luck with getting the parts together and the build in general! And I hope your health continues to improve and strengthen! 

Cheers 

Bennie

[Numbchux]

4.444 and 1.59 gears interfere a bit, and require a bit of machining to clear each other, but it's not too bad.

Some aftermarket LSD front diffs do not clear low range gears.

I have a FT4WD, D/R EA82 gearbox apart and modified for 1.59 low, 4.444 EJ R&P, 23 spline stub axles, phase 2 EJ center diff (if I ever got motivated again, I'd send this off to be rebuild to 20kg), and a carbonetic clutch-type front LSD.  When I went to assemble, and realized that the low range is hard against the front diff....I walked away. That was probably 5 years ago.... I can't really bring myself to put much into it, as our bone-stock '04 H6 Outback with the 4EAT is faster, more comfortable, almost as capable (would be with a 2" lift), and easier to drive (on and off road). 

[el_freddo]

@Numbchux: Sell the R&P gears plus the locking centre diff with housing to @ellie-ray? 

Cheers 

Bennie

[ellie-ray]

Thanks again Bennie and thank you too for the extra info Numbchux!

On 6/8/2020 at 7:51 AM, el_freddo said:

Low range oil feeders on this page. Pics will tell you more with way less words! 

Haha true, cheers!

Great info on the cut and shut job, makes a lot of sense about the bevel.

On 6/8/2020 at 7:51 AM, el_freddo said:

I hope your health continues to improve and strengthen! 

Thanks mate! Appreciate it!

19 hours ago, Numbchux said:

4.444 and 1.59 gears interfere a bit, and require a bit of machining to clear each other, but it's not too bad.

Some aftermarket LSD front diffs do not clear low range gears.

Great to know!

 

19 hours ago, Numbchux said:

our bone-stock '04 H6 Outback with the 4EAT is faster, more comfortable, almost as capable (would be with a 2" lift), and easier to drive (on and off road). 

Yeah I have seriously considered just doing up a forester or something like that but I have always had a serious thing for the L series, I can't really describe it but they just feel so right to me. Plus I have dreamed about this for years and am prepared to spend a fair decent amount to get it the exact way I want it (custom progressive longer travel suspension system and many more cool bits), although it may take me a while to do so.

When I get this going I will definitely post a build thread as I'm sure I will need some more advice along the way!

Thanks again Bennie and yes Numbchux, if you decide you don't want that gearbox please let me know and I'm sure we can work something out.

Lincoln

 

[Numbchux]

Mine is not set up for a locking center. Way too much work, IMHO.

 

I post it all up for sale periodically...but I've got about $1k into the R&P and front diff alone, not to mention 3 donor transmissions for various components and I'm not ready to take a loss on it.

[ellie-ray]

Yeah fair enough mate. Cheers for the advice.

[el_freddo]

On 6/9/2020 at 1:45 AM, Numbchux said:

I have a FT4WD, D/R EA82 gearbox apart 

 

On 6/10/2020 at 12:16 AM, Numbchux said:

Mine is not set up for a locking center.

If you’ve got the EA82 FT4wd box, it would have the locking centre diff and 3.7 or 3.9 diff ratio. What Ellie-Ray needs is the centre diff with matching housing, the ring gear and pinion shaft - that’s essentially what Ellie-Ray is chasing for this build. The rest can be sourced locally. 

And I’m not his agent, just thinking out loud - I haven’t spoken to Ellie about gathering parts. 

Cheers 

Bennie

[Numbchux]

Yes, what I have is not what he's looking for, not for sale, and on the other side of the planet.

 

If you want to split hairs, it is comprised of parts from an EA82 RX FT4WD DR box, standard EA82 PT4WD DR box, and phase 2 EJ AWD box, plus many new parts. Pretty sure I scrapped the 3.7, 3.9 and 4.11 R&P that came with all 3, as well as the FT4WD center and PT4WD transfer. It has a new 4.44 R&P unmodified, because I had planned to use the phase 2 center diff. It has the 1.6:1 low from the PT4WD, although I saved the 1.2:1, but I don't think that will clear the Carbonetic diff either.

 

All of that for a 25:1 crawl ratio. When my 4Runner has a 29.5:1 AND a torque converter.

[el_freddo]

Fair enough. I didn’t think it would hurt to ask. 

Cheers 

Bennie