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IROCDUDE89

5 speed dual range fulltime 4wd questions

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Alright my transmission swapped brat guys. Looking to either get a 5 speed d/r or if I can find one 5 speed d/r fulltime 4wd with the center diff lock. But my question is what does it take to make the fulltime 4wd one work in my brat and can you swap the 3.9 into it and also the rear lsd and can you swap the 1.5 lo gear into one. Also if you have everything I need for sale for a swap post it too. Thanks

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Fulltime w/difflock swap is exactly the same as regular EA 5spd d/r swap.  with the exception that you need to add switching solenoids in addition to the d/r lever hookup.  Easy, use Single range pushbutton solenoids and spdt switch.

It is possible to put the 1.59 reduction into the FT box.  Good chance to put the 23 spline stubs in the front diff, casue there isn't an easy option for 25 spline axles in the Brat (unless you got EA82 front)  

It is NOT possible (to my knowledge)  to swap the final drive to 3.9 or 4.11,  as there was never a correct pinion shaft in that ratio for the FT4wd box.

So you'd end up with tall first gear.  Funny thing is those boxes have LOWER ratio 2nd through 5th.  So it offsets the 3.7 ratio a little bit.

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Agreed with FerGloyale. 

I believe there is the FT4wd box in 3.9 ratio but it’s a difficult one to find. 

If you want a better diff ratio the only way to do it is to customise the pinion shaft.  I’ve got 4.111:1 in mine and it works a treat. I do wish I put in the extra effort/coin and got 4.44:1 though. 

If you do got for a 4.xx ratio you’ll need to also shave the crown wheel to clear the larger L series low range gears. 

Mince you’re running one of these boxes there’s a coupe of “rules” to keep the centre diff happy:

1) always run tyres of the same make/model with the same pressure!

2) once on anything remotely loose/slippery LOCK THE DIFF!  This will reduce the possibility of one axle spinning faster than the other. Locking the diff in these situations will prolong the life of the diff (which is hard to find in good condition these days!).

Cheers

Bennie

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1 hour ago, el_freddo said:

Agreed with FerGloyale. 

I believe there is the FT4wd box in 3.9 ratio but it’s a difficult one to find. 

If you want a better diff ratio the only way to do it is to customise the pinion shaft.  I’ve got 4.111:1 in mine and it works a treat. I do wish I put in the extra effort/coin and got 4.44:1 though. 

If you do got for a 4.xx ratio you’ll need to also shave the crown wheel to clear the larger L series low range gears. 

Mince you’re running one of these boxes there’s a coupe of “rules” to keep the centre diff happy:

1) always run tyres of the same make/model with the same pressure!

2) once on anything remotely loose/slippery LOCK THE DIFF!  This will reduce the possibility of one axle spinning faster than the other. Locking the diff in these situations will prolong the life of the diff (which is hard to find in good condition these days!).

Cheers

Bennie

How'd you get 4.11 gear, who done it and how much

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2 hours ago, FerGloyale said:

Fulltime w/difflock swap is exactly the same as regular EA 5spd d/r swap.  with the exception that you need to add switching solenoids in addition to the d/r lever hookup.  Easy, use Single range pushbutton solenoids and spdt switch.

It is possible to put the 1.59 reduction into the FT box.  Good chance to put the 23 spline stubs in the front diff, casue there isn't an easy option for 25 spline axles in the Brat (unless you got EA82 front)  

It is NOT possible (to my knowledge)  to swap the final drive to 3.9 or 4.11,  as there was never a correct pinion shaft in that ratio for the FT4wd box.

So you'd end up with tall first gear.  Funny thing is those boxes have LOWER ratio 2nd through 5th.  So it offsets the 3.7 ratio a little bit.

But can you swap 3.7 for the 3.9. I don't know nothing about the 4.11 in these

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I used the 3.9 gears from an XT6 transmission to swap my 3.7 FT DR box so it is possible. I also swapped the axle stub shafts so it would bolt in to my EA81 Wagon. It took parts from 3 different transmissions to make mine but it was worth it.

Edited by Crazyeights

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1 minute ago, IROCDUDE89 said:

But can you swap 3.7 for the 3.9. I don't know nothing about the 4.11 in these

No.  Not with stock parts.  D/R Locking diff boxes like this in 3.7 in the RX only.  

I suppose there is the 3.9 Fulltime single range box from XT6....you could use that R+P.  But you'd also need to swap the entire lower gear/synchro set from the 3.7 box onto the pinion shaft (Different ratios for 2-5, and second is cast into upper shaft pf D/R so you gotta keep the gears that match it) so now you need 3 boxes to make one, and 2 of those are already rare as hens teeth to find.  

Perhaps a custom pinion could be welded up on a lathe?

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Mine was a custom job. The 4.111:1 ring and pinion came from a forester box or a dead wrx single range box. 

I don’t know what this would cost as I purchased my initial 4.111:1 modified L awd pinion shaft with its matching ring (crown) gear.

That wasn’t the best work, and a few years later I sheared off the weld - turned out it only had 2mm of penetration. I was visiting mates 3500km from home, so wasn’t exactly a convenient time for this to happen (better than the middle of the Nullarbor though!!).

Through the Subi mate’s network someone knew someone else that owed them a favour - and we got a new shaft made up from the broken one, and the job was done properly this time!  The shaft was beveled, had a male stub on one piece and a female section on the other to help mate and centre the two parts together, these were pressed together. 

Then a specific welding process was used to fill the beveled section with layers etc. it was a very deep weld and a slow one to complete. Then a “cap weld” was done to finish the welding off. This cap weld was then machined flat to the height of the rest of the shaft. Bloody artwork!!  It had a slight bend in it - about .1 thou - but then we worked out that the lathe has .04 of free play in the clutch so it was probably a lot closer to dead straight A’s humanly possible.  No vibrations so all is good!

The most astonishing bit was that the floor manager of the workshop allowed the work pro bono!

So a couple of slabs of beer were promptly arranged!

To work the cost out though I had a welder and a machinist working on the shaft for close to five hours. It didn’t seem to take that much time while we were there!  But it was a bit of involved process - and having the two experts there collaborating with each other sped up the time that it may have taken if I were doing this at home at a local shop.

It is well worth the effort, but consider going the 4.44 ;)  R180’s are much easier to find in 4.44 and air or elockers are available for this diff - of course mods must be done to make either fit though!

That’s my next project!!

Cheers 

Bennie

 

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8 hours ago, el_freddo said:

Mine was a custom job. The 4.111:1 ring and pinion came from a forester box or a dead wrx single range box. 

I don’t know what this would cost as I purchased my initial 4.111:1 modified L awd pinion shaft with its matching ring (crown) gear.

That wasn’t the best work, and a few years later I sheared off the weld - turned out it only had 2mm of penetration. I was visiting mates 3500km from home, so wasn’t exactly a convenient time for this to happen (better than the middle of the Nullarbor though!!).

Through the Subi mate’s network someone knew someone else that owed them a favour - and we got a new shaft made up from the broken one, and the job was done properly this time!  The shaft was beveled, had a male stub on one piece and a female section on the other to help mate and centre the two parts together, these were pressed together. 

Then a specific welding process was used to fill the beveled section with layers etc. it was a very deep weld and a slow one to complete. Then a “cap weld” was done to finish the welding off. This cap weld was then machined flat to the height of the rest of the shaft. Bloody artwork!!  It had a slight bend in it - about .1 thou - but then we worked out that the lathe has .04 of free play in the clutch so it was probably a lot closer to dead straight A’s humanly possible.  No vibrations so all is good!

The most astonishing bit was that the floor manager of the workshop allowed the work pro bono!

So a couple of slabs of beer were promptly arranged!

To work the cost out though I had a welder and a machinist working on the shaft for close to five hours. It didn’t seem to take that much time while we were there!  But it was a bit of involved process - and having the two experts there collaborating with each other sped up the time that it may have taken if I were doing this at home at a local shop.

It is well worth the effort, but consider going the 4.44 ;)  R180’s are much easier to find in 4.44 and air or elockers are available for this diff - of course mods must be done to make either fit though!

That’s my next project!!

Cheers 

Bennie

 

Sound like you just need to sell me your setup so you can start on your next project lol

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14 hours ago, Crazyeights said:

I used the 3.9 gears from an XT6 transmission to swap my 3.7 FT DR box so it is possible. I also swapped the axle stub shafts so it would bolt in to my EA81 Wagon. It took parts from 3 different transmissions to make mine but it was worth it.

Did you use the 1.5 lo gear too or did you leave 1.19 in it

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I left the 1.19 in it. I would like to go back in and put the 1.5x in it but I don't want to tear apart a good dual range for the donor parts. I already had a junk XT6 trans and that's what gave me the idea to use the 3.9 ring and pinion. I wonder if I could fit an LSD carrier in there while I'm at it Hmm....

Edited by Crazyeights

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9 hours ago, el_freddo said:

Through the Subi mate’s network someone knew someone else that owed them a favour - and we got a new shaft made up from the broken one, and the job was done properly this time!  The shaft was beveled, had a male stub on one piece and a female section on the other to help mate and centre the two parts together, these were pressed together. 

Then a specific welding process was used to fill the beveled section with layers etc. it was a very deep weld and a slow one to complete. Then a “cap weld” was done to finish the welding off. This cap weld was then machined flat to the height of the rest of the shaft. Bloody artwork!!  It had a slight bend in it - about .1 thou - but then we worked out that the lathe has .04 of free play in the clutch so it was probably a lot closer to dead straight A’s humanly possible.  No vibrations so all is good!

Cheers 

Bennie

 

Was it oxy-hydrogen plasma spray they used for buildup?

Or electron beam deposition?

Inquired about this 2nd method locally 2 yrs ago but they stated they wouldn't do it because of DOT regs & insurance liabilities.

If for an off-road vehicle they might have done the work, only maybe tho. 

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55 minutes ago, Crazyeights said:

I left the 1.19 in it. I would like to go back in and put the 1.5x in it but I don't want to tear apart a good dual range for the donor parts. I already had a junk XT6 trans and that's what gave me the idea to use the 3.9 ring and pinion. I wonder if I could fit an LSD carrier in there while I'm at it Hmm....

I thought the rx already had a lsd in the front and rear. And could I use the 1.5 gear out of my 4 speed or does it have to be from a 5 speed. And does the 3.9 have to come from xt6 or can I use my my 4 speed one. Sorry I've never really looked at the inside of one and don't really know how the hi/lo works in them. Just trying to figure out what all parts are interchangeable 

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15 hours ago, FerGloyale said:

No.  Not with stock parts.  D/R Locking diff boxes like this in 3.7 in the RX only.  

I suppose there is the 3.9 Fulltime single range box from XT6....you could use that R+P.  But you'd also need to swap the entire lower gear/synchro set from the 3.7 box onto the pinion shaft (Different ratios for 2-5, and second is cast into upper shaft pf D/R so you gotta keep the gears that match it) so now you need 3 boxes to make one, and 2 of those are already rare as hens teeth to find.  

Perhaps a custom pinion could be welded up on a lathe?

So I can't use the 3.9 low gear with 1.5 lo.  Cause i really want the 1.5 instead of the 1.19 Sorry I don't really know how the hi/lo work in these things never looked inside one. 

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1 hour ago, Crazyeights said:

I left the 1.19 in it. I would like to go back in and put the 1.5x in it but I don't want to tear apart a good dual range for the donor parts. I already had a junk XT6 trans and that's what gave me the idea to use the 3.9 ring and pinion. I wonder if I could fit an LSD carrier in there while I'm at it Hmm....

https://www.ultimatesubaru.org/forum/topic/46877-front-diff-interchangeability-the-true-answer/

 

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2 hours ago, IROCDUDE89 said:

I thought the rx already had a lsd in the front and rear. And could I use the 1.5 gear out of my 4 speed or does it have to be from a 5 speed. And does the 3.9 have to come from xt6 or can I use my my 4 speed one. Sorry I've never really looked at the inside of one and don't really know how the hi/lo works in them. Just trying to figure out what all parts are interchangeable 

 

No the RX trans has a standard Open front diff.

None of the 4spd parts will fit into the 5spd.

3.9 from XT6 is the ONLY 3.9 pinion that will have the right diameter and length to accept the RX gears.  3.9 from D/R or S/R  5spds will not be long enough or be right diameter for matching RX gears(too skinny).  An AWD pinion shaft (in 3.9 or 4.11 or 4.44) would be too long, although it will be the right diameter.  I supposed one of those would be the place to start with cutting and welding if you were goin that route.  there is a splined end that engages the lockable diff, so you can't just cut it shorter......you'd have to cut out a roughly 2" section from the middle.  Or cut and mate the tail end of the RX shaft onto the new one.

You can use a standard 5spd D/R lo range set. (1.59:1)  

An OBX or other aftermarket front LSD for WRX etc. should fit inside the D/R box.  But maybe not as the D/R gear set lives directly above the diff, and a larger LSD carrier may not clear the D/R gears.

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Ok, we need to clear a few things up here:

- firstly. When talking about these gearboxes we need to decipher them as PT4WD or FT4WD/AWD licking centre diff gearbox. 

- the EA81 PT4WD gearbox (I’m 99% sure) is fitted with the 1.447:1 and is mounted differently in the gearbox to that of the EA82 gearboxes and the EJ dual range gearboxes that you don’t have. 

- the pinion shaft on the FT4WD (locking centre diff gearbox) is THE LONGEST Subaru have produced to date. 

- EJ pinions do not fit without modifying them with the locking centre diff pinion in the mix. I’m not even sure if it’s possible to modify two EJ pinions to make the required length of the EA locking centre diff pinion box. 

- the locking centre diff gearbox came in two ratios - 3.7 and 3.9.  Dual range and single range were both available. Pinions and ratios from the PT4WD WILL NOT FIT!

- If you want a DUAL RANGE box you’ll need the AWD dual range gearsets. To make a dual range box from a single range box either requires another AWD dual range box (EJ or EA) or to do a super dodgy and match the lower AWD gearset with an upper dual range PT4WD gearset of the same ratios. Not the done thing. 

- the OBX front LSD will fit. With the low range you will need to shave the retainer bolt heads on an angle. I also recommend rebuilding this lsd with the spring and cone washer kit available online.

- the diff centre in this locking centre diff box is OPEN. An lsd cannot be added to this diff. BUT - with an EJ AWD ring, pinion centre diff (with the factory LSD) and marched housing to the centre diff, and the EA dual range AWD gearsets you can effectively build an EJ dual range gearbox - in an EA case.  The EA AWD gearset will fit on the EJ pinion and work with an EJ centre diff. Custom tail shaft, gear linkages and gearbox xmem will be needed.

- PT4WD gearboxes are only “good” for their decent/awesome low range options that can be easily fitted to the L series AWD locking centre diff gearbox

- no factory EA box came with a front LSD

- the AWD locking boxes are rare and spare parts are in the form of other AWD locking boxes

Once home and on the computer I’ll post up some picks of my build with the EJ cases, L series 1.59:1 dual range, 4.111:1 diff ratio and shaved crown wheel, locking centre diff and auxiliary oil feeders to help keep low range cool.

@czny - I don’t know the process used. What ever is used in mining drilling equipment is what was done to my shaft. I’d expect that other parts of the pinion shaft will break before this weld job does. 

@IROCDUDE89 - sorry dude, NOT for sale. Plus shipping would practically double the cost! You be better off buying a low km EJ dual range and drop the DCCD centre diff setup in along with the 1.59:1 low range. 

Cheers 

Bennie

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On 2/1/2019 at 6:27 PM, Crazyeights said:
1 hour ago, el_freddo said:

Ok, we need to clear a few things up here:

- firstly. When talking about these gearboxes we need to decipher them as PT4WD or FT4WD/AWD licking centre diff gearbox. 

- the EA81 PT4WD gearbox (I’m 99% sure) is fitted with the 1.447:1 and is mounted differently in the gearbox to that of the EA82 gearboxes and the EJ dual range gearboxes that you don’t have. 

- the pinion shaft on the FT4WD (locking centre diff gearbox) is THE LONGEST Subaru have produced to date. 

- EJ pinions do not fit without modifying them with the locking centre diff pinion in the mix. I’m not even sure if it’s possible to modify two EJ pinions to make the required length of the EA locking centre diff pinion box. 

- the locking centre diff gearbox came in two ratios - 3.7 and 3.9.  Dual range and single range were both available. Pinions and ratios from the PT4WD WILL NOT FIT!

- If you want a DUAL RANGE box you’ll need the AWD dual range gearsets. To make a dual range box from a single range box either requires another AWD dual range box (EJ or EA) or to do a super dodgy and match the lower AWD gearset with an upper dual range PT4WD gearset of the same ratios. Not the done thing. 

- the OBX front LSD will fit. With the low range you will need to shave the retainer bolt heads on an angle. I also recommend rebuilding this lsd with the spring and cone washer kit available online.

- the diff centre in this locking centre diff box is OPEN. An lsd cannot be added to this diff. BUT - with an EJ AWD ring, pinion centre diff (with the factory LSD) and marched housing to the centre diff, and the EA dual range AWD gearsets you can effectively build an EJ dual range gearbox - in an EA case.  The EA AWD gearset will fit on the EJ pinion and work with an EJ centre diff. Custom tail shaft, gear linkages and gearbox xmem will be needed.

- PT4WD gearboxes are only “good” for their decent/awesome low range options that can be easily fitted to the L series AWD locking centre diff gearbox

- no factory EA box came with a front LSD

- the AWD locking boxes are rare and spare parts are in the form of other AWD locking boxes

Once home and on the computer I’ll post up some picks of my build with the EJ cases, L series 1.59:1 dual range, 4.111:1 diff ratio and shaved crown wheel, locking centre diff and auxiliary oil feeders to help keep low range cool.

@czny - I don’t know the process used. What ever is used in mining drilling equipment is what was done to my shaft. I’d expect that other parts of the pinion shaft will break before this weld job does. 

@IROCDUDE89 - sorry dude, NOT for sale. Plus shipping would practically double the cost! You be better off buying a low km EJ dual range and drop the DCCD centre diff setup in along with the 1.59:1 low range. 

Cheers 

Bennie

Thanks  @el_freddo and @FerGloyale for all the info. I have found a rx tranny with brat stubs already in it. I think I might get it and find someone selling a xt6 3.9 and a 1.5 lo. And that'll be good enough for now might throw a lsd in while I'm at it and find a lsd for the rear later. If you know anyone with parts I need for sell let me know. And if I had the spare money to do a full ej swap I'd go that route. But for for now I just wanna upgrade to a 5speed and I like the thought of getting rid of the PT 4wd since I run mine in 4wd most of the time any way

 

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Just make sure that RX box is AWD if that’s what you want. 

Over here it was pretty rare for an RX to have an AWD box!

I know they’re standard in the RXII coupe. We didn’t get them over here :(

Cheers 

Bennie

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47 minutes ago, el_freddo said:

Just make sure that RX box is AWD if that’s what you want. 

Over here it was pretty rare for an RX to have an AWD box!

I know they’re standard in the RXII coupe. We didn’t get them over here :(

Cheers 

Bennie

Good point.

85/86 RX were Sedans, and here got a PT4wd, D/R 3.7 final drive with 1.19 low range and 25 spline stubs.........Close ratio 2nd-5th gears.

The 87+ RX were I think all or at least mostly Coupes, and here got the Fulltime w/difflock box with all the same ratios.

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Ok, got pics!

This pic shows just how long the L series AWD locking centre diff pinion shaft really is:

lqJzat.jpg

The EJ pinion shaft ends behind where the second straight splined section is.  The OBX LSD is up front.  The L series low range side gears are sitting where they would be with both cases joined together.  You can see how close this comes to the LSD housing.  You might also make out the shaving of the LSD retainer bolts, if not, here's a better pic:

3T8w64.jpg

Locking centre diff, you can see the dog clutch in front of the diff:

fRTUWK.jpg

Here's my first modified pinion shaft with it's very crappy weld job.  Apparently it spent the first part of its life behind an STi turbo engine in a brumby.  I guess my little EJ22 L series was too much for it in some soft sand at Lancellin when it let go (we were loaded up for our trip out west).  No shaving of the crown wheel in this pic.

p4220006rs.jpg

In this pic you can see the shaving on the outer edge of the teeth on the crown wheel:

MnQfeM.jpg

Low range oil feeders for cooling of the low range gears on long hill climbs - works a treat, I have no whining with my low range:

YDkqIN.jpg

For the EA application that's probably about all the pics I have to share.  The others that I have are specific to mods required for the EJ dual range.  All of the above pics are of my L AWD locking centre diff gearbox with a phase 2 (8 bolt) EJ gearbox ;)

I hope that answers a few things for you IROCDUDE89!

And I understand if there's any wet undies, really though, it's kind of expected  ;):P

Cheers

Bennie

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