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Guest Message by DevFuse
 

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- - - - -

4.444 x 1.592 x 3.545 = ~25:1


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39 replies to this topic

#1 Numbchux

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Posted 05 July 2012 - 09:01 PM

Alright, I believe I have everything I need. Couple parts will need some modifying, but it's all there (Except sealant and oil...).

'88 Gl Wagon transmission. This will be the donor transmission for the 1.592:1 Low Range, and 23 spline axle stubs
Posted Image

Also pictured is the center diff housing (the diff and transfer gears are on the shelf) from a '93 Impreza.


An RX FT4WD D/R (Unsure of the exact year of this one, but '87-'89), this will donate most of it's internals, 1-5 gears, input and output shafts:
Posted Image

Also pictured is a brand-new, OEM 4.444 front ring and pinion gearset (Originally looked up for a JDM 5MT, found that part number superseded for a USDM Forester XT).

And a Carbonetic clutch-type front LSD, listed for a 2002-2007 WRX.

Due to a broken off speedometer cable in my RX case, I will probably use the GL PT4WD case. This also means I won't have to swap the low-range idler gear from one case to another.




I have started tearing down the GL trans. Things I've noticed:
It was not difficult to separate the Low Range gearset from the input shaft. Swapping it onto the RX input shaft should be a breeze (knock on wood....)
Posted Image

The 3.9 ring gear (which does clear the 1.59 low range set) is the same outer diameter as the 4.444 gear. BUT, the 4.444 unit is thicker (due to a smaller pinion gear). I have heard that this ring gear will have to be modified to clear the low range gears, but an initial test-fit looks like it might work as-is. But time will tell.
Posted Image

More to come as I make progress....

Edited by Numbchux, 05 July 2012 - 09:10 PM.


#2 The Beast I Drive

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Posted 05 July 2012 - 09:13 PM

This will be awesome to see built and here how it does! Should make driving with 31's feel like stock tires.

-Bill

#3 carfreak85

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Posted 06 July 2012 - 12:13 AM

Yeeessss! :burnout:Subscribed.

#4 Numbchux

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Posted 06 July 2012 - 12:52 AM

Went back at it after dinner....

Got the RX trans pulled apart.

RX pinion next to the FXT pinion:
Posted Image

The RX pinion has a "spacer" (basically just a piece of tube) to take up the extra length. But, pull that off, and the spline adapter, and nut from the RX pinion fit perfectly on the FXT pinion.
Posted Image

I need to get a bearing separator to get that bearing off the pinion shaft. Not the final assembly, but test fit with the FXT pinion in the RX output shaft:
Posted Image

And, proof of concept. RX output shaft and driven gears, no swapping gearsets at all. FXT pinion. Phase 1 EJ center diff:
Posted Image


Now. 1.592 low range gears swapped onto the RX input shaft, and in the PT4WD case, with 4.444 ring gear:
Posted Image

It does hit, ever so slightly. The edge of the teeth on the shifting collar for low range.
Posted Image

Posted Image

I need to talk to machine shops. I think I could have a little material taken off the collar and ring gear, and get the clearance I need.


And, all the mechanicals laid in the one case half.
Posted Image



So, time to talk to a few machine shops about getting the ring gear, shifting collar, and axle stubs modded for this setup. And then put it all back together.


I tell you, I'm REALLY not looking forward to getting the input shaft and drive gears seated in the case. It's a PITA in a single-range trans to get the alignment pins seated in the bearings. Add in all the crap for the dual range....and it's going to suck.

#5 The Beast I Drive

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Posted 06 July 2012 - 12:07 PM

As far as getting the ring gear clearance, I wouldn't take anything off the shift collar for the low range, just off the edge of the gear. Idk if you have a buddy with a lathe, but if you do the easiest way to do it would be to chuck it in the lathe, then set up a rest and use a grinder to carefully grind the edge while it rotates. Then ship it out to be heat/cryo treated.

-Bill

#6 maozebong

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Posted 06 July 2012 - 05:04 PM

ohmahgawd this is amazing.

i sure wanna start making one.

#7 Numbchux

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Posted 07 July 2012 - 01:27 AM

As far as getting the ring gear clearance, I wouldn't take anything off the shift collar for the low range, just off the edge of the gear. Idk if you have a buddy with a lathe, but if you do the easiest way to do it would be to chuck it in the lathe, then set up a rest and use a grinder to carefully grind the edge while it rotates. Then ship it out to be heat/cryo treated.

-Bill


I don't know. I'm not super comfortable taking material off either. But when it comes down to it, it'll probably be cheaper to have it all taken off one piece, instead of some of each. I'm not putting huge power through this, so I think it should be OK.

Don't know anyone with a lathe (that I know of...)...so it'll have to be through a shop.

As for treating it. I have an in with Diversified Cryogenics (aka Frozen Rotors). I was talking to them years ago about cryo treating D/R internals when I wanted to put power through them. They recommended not going that route, as cryo treating means the metal can't flex, which actually makes it brittle. For transmission internals, it's not an improvement.





In other news.....I found this...
http://forums.nasioc...d.php?t=2377483


So tempting. But I think I'll run this center diff a bit first, see if it actually needs to be upgraded. Swapping it out in the vehicle is actually not very difficult.

Edited by Numbchux, 07 July 2012 - 01:30 AM.


#8 The Beast I Drive

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Posted 07 July 2012 - 01:31 PM

That would be the tits with DCCD!

I had my 4.88 ring and pinions in my Yota axles cryo treated by Longfield Superaxles, so far they have been working great... I would at least just do the treatment on the ring gear after the material is removed, I didn't really give much thought to the pinion shaft being a main part of the tranny, being as long as it is it would be bad to be brittle... But it should help the ring gear.

-Bill

#9 Gloyale

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Posted 10 July 2012 - 07:36 PM

As far as getting the ring gear clearance, I wouldn't take anything off the shift collar for the low range, just off the edge of the gear. Idk if you have a buddy with a lathe, but if you do the easiest way to do it would be to chuck it in the lathe, then set up a rest and use a grinder to carefully grind the edge while it rotates. Then ship it out to be heat/cryo treated.

-Bill


I took a few thousands of an inch off the collar.

the rest I just mounted up the diff to a stationary bearing retain cup, and used a grinder on the edge. The lathe would work too.

wet grind, no treating needed afterword.

that was to make a 4.11 R+P work with the 1.59 low.

#10 Numbchux

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Posted 13 July 2012 - 02:54 PM

Found out a friend of mine has a lathe at his shop. Dropped off the parts there, he's very confident that he can make it happen. He thought it would be best to chamfer the ring gear, and not modify the collar at all.

Ordered a bearing splitter, so I can put swap bearings onto the pinion and front diff.

#11 Numbchux

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Posted 16 July 2012 - 10:45 PM

Bearing splitter came today. 4.444 pinion gear has a bearing on it. Carbonetic diff has side bearings.

I did notice, that even once I got the bearing and washer pressed onto the pinion, something was a different length, and that the nut wouldn't be able to tighten things up properly....

Compared that little spline adapter to an EJ one....yep, there's the problem:
Posted Image

Diameters and spline counts are the same, but length is slightly different. Good to know, and got it straightened out.


Machine work should be done in a few days. Then I can put the trans back together.

Then I can start the project of putting it in the brat (along with the EJ18 swap....). Then I can have the driveline modified, etc. etc.






that DCCD hasn't sold yet.....might throw him a lowball....

#12 daredevil1166

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Posted 18 July 2012 - 06:39 PM

Really cool.

A couple of questions so I can understand better.

Why use the AWD center diff?

Is it not possible to keep the PT transfer case?

Why the RX input and and output shafts? Could you not use the GL ones?

What was the original ratio of the RX trans?

Edited by daredevil1166, 18 July 2012 - 06:43 PM.


#13 Numbchux

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Posted 18 July 2012 - 08:57 PM

Really cool.

A couple of questions so I can understand better.

Why use the AWD center diff?

Is it not possible to keep the PT transfer case?

Why the RX input and and output shafts? Could you not use the GL ones?

What was the original ratio of the RX trans?


As you can see in the pics, the pinion shaft is a drastically different length between the FT4WD and AWD setups, so the center diff has to match the pinion or major fabrication becomes necessary. I've seen the stock VLSD center diff perform offroad, and am fairly confident in it's strength. And if it turns out to be insufficient, the Group N unit (5 times stronger than stock) or DCCD are both simple swaps, and probably less than a cut and weld and treatment on a pinion shaft.

PT4WD transmissions have the pinion shaft as part of the output shaft. They are not seperable. So the output shaft must come from a FT4WD or AWD unit. And the input shaft is unique to the dual range. The only way to get both with USDM parts without mixing and matching, is the RX box.

RX originally was 3.7 axle ratio, and 1.192 low range.

#14 ShawnW

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Posted 19 July 2012 - 04:17 AM

As you can see in the pics, the pinion shaft is a drastically different length between the FT4WD and AWD setups, so the center diff has to match the pinion or major fabrication becomes necessary. I've seen the stock VLSD center diff perform offroad, and am fairly confident in it's strength. And if it turns out to be insufficient, the Group N unit (5 times stronger than stock) or DCCD are both simple swaps, and probably less than a cut and weld and treatment on a pinion shaft.

PT4WD transmissions have the pinion shaft as part of the output shaft. They are not seperable. So the output shaft must come from a FT4WD or AWD unit. And the input shaft is unique to the dual range. The only way to get both with USDM parts without mixing and matching, is the RX box.

RX originally was 3.7 axle ratio, and 1.192 low range.


I think the only other trans that might make a nice donor is a Xt6 5MT but I haven't been able to get enough time to clear every workbench in my shop to have all the tranny's apart at once. As a bonus those are 3.9, and I think some have the spot to mount the lo range stuff in them already cast to the case.

#15 The Beast I Drive

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Posted 20 July 2012 - 09:43 PM

I think the only other trans that might make a nice donor is a Xt6 5MT but I haven't been able to get enough time to clear every workbench in my shop to have all the tranny's apart at once. As a bonus those are 3.9, and I think some have the spot to mount the lo range stuff in them already cast to the case.


Machining would be required on the case to make dual range work with the xt6 case, the input shaft area has to be drastically changed to accept the low range gear shaft and the input bearing from the dual range. I've noticed the early legacy manual trans have a case almost identical to the RX case, the only difference being the belhousing (obviously) and the lack of the dual range specific parts, but all the bumps and bungs are there, just need to be machined to accept the dual range parts.

-Bill

#16 Gloyale

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Posted 21 July 2012 - 10:41 AM

I think the only other trans that might make a nice donor is a Xt6 5MT but I haven't been able to get enough time to clear every workbench in my shop to have all the tranny's apart at once. As a bonus those are 3.9, and I think some have the spot to mount the lo range stuff in them already cast to the case.


I have an XT Turbo FT4wd, a standard 3.9 D/R, and a 4.11 legacy trans here.

Plans are:

D/R case and input shaft.

FT4wd gear sets(pressed off, and pressed onto D/R upper, and AWD lower)

4.11 awd pinion

AWD center/transfer section.


with this recipe I can use a stock D/R case, with no lo gear swapping.

The key to this one is that the FT4wd 1st and 2nd gears match the stock D/R input shaft casting......and the FT4wd 3rd, 4th, and 5th gears will fit onto the AWD output shaft.

The single range FT4wd boxes are just slightly easier to find than the RX boxes

#17 Numbchux

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Posted 25 July 2012 - 12:07 AM

I think the only other trans that might make a nice donor is a Xt6 5MT but I haven't been able to get enough time to clear every workbench in my shop to have all the tranny's apart at once. As a bonus those are 3.9, and I think some have the spot to mount the lo range stuff in them already cast to the case.


Thought I replied to this...


The XT6 trans does not have the low range stuff any more than the phase 1 EJs do. The case is shaped to leave room for the gears, but it would still require some serious machining to get everything to mount up. IMHO not worth it.

Here's some phase 1 EJ gears laid in an XT6 case:
Posted Image


I think the XT6 trans might have the ticket that might not require the RX donor, though. You could probably mix and match input and output shafts like GLoyale did (He used an EJ ouput shaft and gears, which didn't work out). As the N/A PT4WD Dual-Range and XT6 FT4WD trans have the same gear ratios, but likely not the difference in hypoid cuts by using the EJ ouput shaft and gears. But this is just speculation....






Got the circlips and case gaskets from the dealership today. Going to stop by my buddy's shop tomorrow to see if the machining is done. I'll be out of town for the weekend, so I won't be able to test-fit until next week sometime....but it's getting close.

Then I have to find time to strip another EJ harness....and put the whole mess in the brat. And THEN, I have to measure the driveshaft and have that modded. Oh yea, and find my 4.444 rear end. I took a glance in my shed today, and only saw a 3.7. Maybe tear apart some of my spare axles to make some deep-DOJ rear axles.



I also was looking at a gear calculator, comparing my 4.3Runner setup to the Brat...

4.3Runner, 4L60, Toyota 2.26 Low, Toyota 4.10 axles, 35s:
3.06 x 2.26 x 4.1 = 28.4
3k rpm in 1st Low = 961 feet/minute

Brat, on 29s:
3.545 x 1.592 x 4.444 = 25
3k rpm in 1st Low = 909 feet/minute



The 4.3Runner is an Auto, so it has the torque converter. But the Brat is a LOT lighter. With the EJ MPFI, it should be a very capable rig. Especially with the front LSD, and hopefully an auto-locker in the rear :headbang:

Edited by Numbchux, 25 July 2012 - 12:23 AM.


#18 turbosubarubrat

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Posted 25 July 2012 - 12:56 AM

cant wait to see the brat:headbang:that thing is going to be awesome and kick rump roast:cool:any pics or threads of the brat:brow:

#19 Numbchux

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Posted 12 October 2012 - 08:17 PM

Was working on the 4.3Runner a lot. But it has earned itself a spot at the bottom of my priority list for awhile :-p


Which means, Brat is back at the top. Brought my case down to the shop so we could grind a bit and test fit to get it just right. Got the ring gear modded just enough. After numerous test-fits in the one case half, I was pretty satisfied with the fit. So I put the other case half on just for a try. And something was major hitting. Couldn't figure it out, but definitely a gear hitting something solid. Not good.


Laid everything in the other case half....and found the problem. The Carbonetic LSD case is hitting one of the low range gears.

As you can see in this picture. The LSD has a larger, squared off shoulder, and the stock front diff is much more rounded. Red arrow pointing where contact is happening.
Posted Image

It's hitting the lower left gear of the 4 in this picture:
Posted Image


Not sure what to do from here. I think I need to take some measurements and see just how much material would have to come off to get that to clear, and debate whether I want to do that, or use a different front diff.

#20 el_freddo

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Posted 12 October 2012 - 08:52 PM

Numbchux I'm loving your work! And I'm jealous that you're playing with gearboxes and I'm not at the moment (I'm trying to source a few bits for my build).

The clearance issue you're having with the LSD and the side gears on the low range: how badly are the fouling eachother? The gearbox I've had built we shaved the same area including bolt heads to clear these gears. The amount taken off doesn't impact on the integrity of the bolts or the LSD in general.

I'll be keen to hear what revs you'll be doing at cruising speed - and can you match a speedo drive gear to show true speed on the dash/instrument cluster?

And I have to ask - what's the plan for the RX FT4wd R&P gears and the centre diff? I'm chasing one (or two, or three :twisted: ) for my build - the unit I've got has been flogged within a thou of it's life, that's all.

Cheers

Bennie

#21 Numbchux

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Posted 23 October 2012 - 08:25 PM

Bah. After some measuring and consultation, I've decided that modifying this diff would be an extremely bad idea. I would have to take about 80% of the material off, all the way around. And while it's not massively load bearing, it would still probably ruin a brand-new diff that retails for more than I've paid for most of the cars I've owned....



So..... 1.2:1 Low range. Would give me about an 18.8:1 Crawl Ratio. Which is, meh. But, would mean I could plow on with what I have.


Use an open front diff. This would require new front axle stubs, as the ones I have have been modified for the Carbonetic front diff. I'd get to keep the awesome gears, but loose the awesome front LSD.



Or, find a different brand front LSD that might be a bit smaller where it counts. EDIT: Just did some research on this front. Most front LSDs are Helical (don't want), and/or have male 25-spline axle stubs built into them. Either of these are deal breakers.....



I don't really like any of those options.

Edited by Numbchux, 23 October 2012 - 08:40 PM.


#22 el_freddo

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Posted 25 October 2012 - 05:43 AM

Just did some research on this front. Most front LSDs are Helical (don't want), and/or have male 25-spline axle stubs built into them. Either of these are deal breakers.....


Numbchux, why don't you want a helical front LSD? This is the option I've gone for - two reasons: 1) no need to split gearbox to tweak like a clutch pack LSD over time and 2) it was cheap enough to add it in while the box was apart (OBX LSD) - I'd be kicking my self if I didn't do it...

I'm guessing this is going into a brat or MY of some sort as there's no off the shelf drive shafts with the 25 spline count - which to me is the reason why you want to steer clear of the 25 spline count out put shafts of the diff.

Personally I'd be going for low gearing over the LSD, but that's just me.

Cheers

Bennie

#23 Numbchux

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Posted 25 October 2012 - 11:05 AM

Because a helical diff does not work unless there's some resistance at both wheels. It works fine in the sand, gravel, snow, even pretty well on ice. But if you lift a wheel off the ground, you've got basically nothing.

And yea, going in a brat. 23 spline very preferred.

#24 kanurys

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Posted 25 October 2012 - 01:35 PM

Maybe you could combine the torsen with a front parking brake setup so it could drag slightly when you need the torsen style diff to transfer power. Just a silly idea... or dual separate parking front parking break levers ??? then you could even just run the open diff...

Man that sounds wacky now that I write it.

#25 Numbchux

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Posted 25 October 2012 - 07:08 PM

Maybe you could combine the torsen with a front parking brake setup so it could drag slightly when you need the torsen style diff to transfer power. Just a silly idea... or dual separate parking front parking break levers ??? then you could even just run the open diff...

Man that sounds wacky now that I write it.


I had the dual ebrake setup on one of my lifted wagons, it worked pretty well, and would probably be pretty effective with a torsen. But, I'm not using the POS OBX, Cusco and Modena are very expensive. None of those options can be done with 23 spline stubs, and probably still wouldn't solve my clearance issues.

I think with the EJ swap and a nice, forgiving clutch I wouldn't NEED the extra gearing. So I'm leaning more towards the LSD.




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