Welcome to the next contribution to the
The Official Pirate4x4.com Jeep Talk Bible (http://www.pirate4x4.com/forum/showthread.php?t=705122)

Topic of the Month MJ/XJ/ZJ T-case Doublers

Show pics of your MJ/XJ/ZJ Transfercase Doublers. Provide specs like spine counts Input/Output, spacer size, cost, overall length, gear reduction options.


This is not a what trans/tcase do I have thread.

Tell us what works good for you an what you would do different.

Few pics of my DIY 231/231 doubler:

Input shaft is made by Local guy who build gears for rally cars, 100€ for shaft. 23 spline

http://static.petrisimolin.com/gallery/data/images/Jeeper-131%20001.jpg

http://static.petrisimolin.com/gallery/data/images/Jeeper-131%20004.jpg

http://static.petrisimolin.com/gallery/data/images/Jeeper-131%20008.jpg

http://static.petrisimolin.com/gallery/data/images/Jeeper-131%20010.jpg

http://static.petrisimolin.com/gallery/data/images/Jeeper-131%20012.jpg
http://static.petrisimolin.com/gallery/data/images/Jeeper-131%20013.jpg
http://static.petrisimolin.com/gallery/data/images/Jeeper-131%20011.jpg

http://static.petrisimolin.com/gallery/data/images/Jeeper-Laatikot.jpg

http://static.petrisimolin.com/gallery/data/images/Jeeper-Mitta.jpg

Here's my doubler thread...

http://www.rockhardxj.com/viewtopic.php?f=2&t=1686

Specs are...


231 crawl box w/ modified shift fork
241hd internals with 6 gear planetary & welded pins
Dana 300
homemade flip kit and atlas twin sticks
32 spline input and outputs
Future plans for lomax 4:1


Currently the reduction ratios are...

1:1
2.62:1
2.72:1 &
7.13:1

Once the Lomax 4:1 gears go in it'll be...

1:1
2.72:1
4:1 &
10.88:1

As far as the length, I haven't actually measured it...but is should be about the same as a standard 231 without the sye.

It should also weigh about 125lbs. fully dressed with oil and everything.

Here's a shot of the completed crawl box...

http://i46.photobucket.com/albums/f144/thetvaman/Jeep/P1010064-1.jpg

And here's a shot of the almost complete Dana 300...

http://i46.photobucket.com/albums/f144/thetvaman/Jeep/P1010050-3.jpg

http://i46.photobucket.com/albums/f144/thetvaman/Jeep/P1010053-2.jpg





Hope all that helps someone.

http://i185.photobucket.com/albums/x42/BrassMunkey4/HPIM1831.jpg

http://i185.photobucket.com/albums/x42/BrassMunkey4/HPIM1832.jpg


231-300 doubler, driver drop. Had to flip both the 231 and the dana 300 for the kit.

I used the madrooster kit, but I would go with the D.D. machine kit if I had to do it over again. More clocking options being the main reason, and fill/drain holes.

Driveshafts are lengthened stock front XJ shafts, since the front yoke bolts on the front and rear of a dana 300.

Shifters are custom, using the parts from Vetteboy's thread about shifter cables (from McMastercarr)

21 spine out of the t-case, 23 spline 300

Crawl box plate and shaft $400 (didnt have any clocking rings in stock)
3/8" dana 300 clocking ring $60
Welding of 231 $60
Shifters $110

Total cost $630

So far so good, only have one run on it tho

BrassMunkey,
Looks like a sweet set up. i ordered my cables yeasterday and I plan on doing the same shifter set up. Yes I have researched BUT could I get another picture of how you mounted the cables to the shift rails on the 300? Thanks for the help!

Here's how I did mine. 1/4" flat stock fits right into the shift rail so I drilled a thru hole, put a bolt down where the pins used to be, and welded a coupling nut on the end that matched the cable.

http://www.pirate4x4.com/forum/gallery/files/3/1/6/2/1/DSC03694.JPG

Ignore the broken doubler in the background. :laughing:

DD Machine Box4Rocks 231 doubler. Front case is a 21 spline input with a 23 spline output to the rear 231 case. I think it was about $400 when I picked it up. Both cases have 2.72 gears. In a long bed MJ.

Gear choices:
2WD rear high
2WD rear low
4WD high
4WD low
4WD double low (7.4)

http://i143.photobucket.com/albums/r127/reson46/MJ/Doubler/IMG_5128.jpg

Sledge hammer provided room for the rear case. I had to cut out the extra bracing for the seat belt to make enough room. I replaced it with a piece of 1/4" flat stock bent to follow the new shape of the floor.
http://i143.photobucket.com/albums/r127/reson46/MJ/Doubler/IMG_4984.jpg

Added a mount to help support the extra case.
http://i143.photobucket.com/albums/r127/reson46/MJ/Doubler/Mount/IMG_5157.jpg

Shifters.
http://i143.photobucket.com/albums/r127/reson46/MJ/Doubler/Shift%20Linkage/IMG_5142.jpg

http://i143.photobucket.com/albums/r127/reson46/MJ/Doubler/Shift%20Linkage/IMG_5137.jpg

What would I do differently?

First I would have changed the o-rings where the shift linkage enters the case while I had everything apart. It has leaked from the beginning and I don't really feel like taking everything apart again. :shaking:

My other concern is the chain on the rear case. Not sure how long it will like putting up with double low. But, I hope not to put it through many full throttle double low runs. I mainly wanted double low for more control going down hill. Usually it just stays in single low. If it does blow, at least I got it for a good price. I have considered upgrading to the 231HD internals. If one falls in my lap I'll consider it more seriously.

Willy

I run a 203/205 in my xj. Not sure on total length of it. The 203 is a dodge 23 spline input behind an aw-4, the 205 is a factory ford. I dont rember its spline count. Doubler is a jed's machine with billet shaft. Total cost was about $800. I have twinn sticked the 205 too. So it has 2wd, 2wd 1.96 low, 2wd 3.83 low low, front digs in both lows and 4wd, 4wd 1.96 low, 4wd 3.83 low low. I would probalby go with a differnt rear case flipped 300 maybe, but the 205 was free so its all good.

http://i16.photobucket.com/albums/b25/xjghost/NP203%20205/203205001.jpg

http://i16.photobucket.com/albums/b25/xjghost/NP203%20205/203205test030-1.jpg

http://i16.photobucket.com/albums/b25/xjghost/NP203%20205/203205test026-1.jpg

http://i16.photobucket.com/albums/b25/xjghost/NP203%20205/203205xmember028.jpg

http://i16.photobucket.com/albums/b25/xjghost/NP203%20205/203205003.jpg

http://i16.photobucket.com/albums/b25/xjghost/NP203%20205/203-205crossmember018.jpg

http://i16.photobucket.com/albums/b25/xjghost/NP203%20205/203-205crossmember019.jpg

Biggest problem was when I cocked the 205 flat it came into the cab so much I had to completly redo the seat mount. Which was planned with a cage but the cage was not going to be done yet. So I ended up going ahead with the cage. Still have more cage work to do. Biggest mistake was thinking a 9"/D44 would survive behind this with 36" IROC's. One 44 unjoint broken, one front shaft, and most recently I spit the pinion gear out the side of the 9" third member. Is that kinda what you are looking for ash?

I went from the stock 4.0L 5speed stock 231 with a SYE, to a V8 Th400 Auto doubler... HUGE difference!

doubler adapter back then was $450
203s go for $50-100
205s go for $50-100
I have $500 into this setup (not including the motor swap)

I use the NP203-NP205 doubler. The NP203 I used on the th400 auto is a 1979 27 spline input Chevy 1 ton t-case.

Pictured here is a XJ Aw4 at the top left, a HUGE NP203 from a 1979 Dodge (23 spline input) in front and a 1979 Ford NP205 (black)
I changed my mind on doing the 4.0L-AW4-203-205 and went to a SBC-th400-203-205
http://www.wheelingarizona.com/forums/files/thumbs/t_203-big_202.jpg
(http://www.wheelingarizona.com/forums/files/203-big_202.jpg)

Here you can see the 203 taken apart and only the gear range section slid onto the AW4 (not mounted). The output shaft can be re used, cut and re splined.

http://www.wheelingarizona.com/forums/files/thumbs/t_203-205_800.jpg (http://www.wheelingarizona.com/forums/files/203-205_800.jpg)

I bought the JEDS 203-205 adaptor from http://www.stazworks.com/
Not welded, I clocked it to where I wanted, pre heated it in the oven then welded it.
http://www.wheelingarizona.com/forums/files/thumbs/t_203-1_587.jpg
(http://www.wheelingarizona.com/forums/files/203-1_587.jpg)


Next I wanted to split the 205 case, A Slip case will allow front wheel drive only, The d300, d20 and NP205 t-cases can be slipt. To make a NP205 a split case, I removed the shift rail closest to the input of the 205.

I carefully gridded the notch on the left to .9in total the notch at the right I lengthened by .4in then tapered it. This picture I found in a write up.
http://www.wheelingarizona.com/forums/files/205shiftrails_648.jpg

Then I welded some 3/8 to the shift rail so My linkage would fit around the 203 adaptor.
http://www.wheelingarizona.com/forums/files/thumbs/t_205-1_705.jpg
(http://www.wheelingarizona.com/forums/files/205-1_705.jpg)

More cutting, I could not make the factory seats fit with the big 205 through the floor
http://www.wheelingarizona.com/forums/files/100_0590_s_180.jpg

I made two large shifters for the 205. I used a stock XJ Auto cable shifter with modified detents for the 203 shifter, and I modified the gates on a B&M shifter for the auto so I can easily get to revers.
http://www.wheelingarizona.com/forums/files/thumbs/t_shifters1_555.jpg
(http://www.wheelingarizona.com/forums/files/shifters1_555.jpg)

http://www.wheelingarizona.com/forums/files/thumbs/t_gauges_389.jpg
(http://www.wheelingarizona.com/forums/files/gauges_389.jpg)

I wanted the reliability of 1ton gear drive cases, the weight was not a big concern for me. The size is not desirable but can be dealt with. The gearing is ok with 400+ ft/lb but Id like it alittle lower for some stuff.

Next time around Ill want to reduce all the weight I can and these cases will have to go. The Length and height makes it really hard to fit. Next time around I should be able to afford the atlas 4speed with the 5:1, lighter, smaller, shorter. But for fractions of that cost the doubler works great.

I have a question about the main crossmember placement that I haven't been able to find a clear answer on. Does the tranny crossmember need to be notched or moved/lowered from it's stock location to clear the front driveshaft at full droop? I have a ZJ with clayton's crossmember and was wondering what if the new longer front driveshaft would make contact with the crossmember.

Thanks,
Fred R.

I have a question about the main crossmember placement that I haven't been able to find a clear answer on. Does the tranny crossmember need to be notched or moved/lowered from it's stock location to clear the front driveshaft at full droop? I have a ZJ with clayton's crossmember and was wondering what if the new longer front driveshaft would make contact with the crossmember.

Thanks,
Fred R.

When I did my doubler there was no way to keep the standard xj crossmember bc the DS would hit it just sitting there. I opted to build a 2x2x.25 one between the 203 and 205. What cases are you going to run?

My plan is to hopefully run a flipped D300 behind a 231 doubler, picked up a D300 for $50 :smokin:. With regards to the crossmember you built, is it only supporting the 203/205 or are you supporting the transmission in some way? How bad would the front driveshaft have hit on the stock crossmember, do you think I could get away with just notching the crossmember and supporting the notch with some plate?

Thanks again,
Fred R.

I used a stock XJ Auto cable shifter with modified detents for the 203 shifter

This was my plan for my 231, did yours still have the plastic ends on the cable? if so have they held up??? the dedents are so tough on a 231 I'm thinking of threading the rod for small heims.

Doubler is a made by a local he doubed the "FOXBOX"... Np231D HD from a dodge dakota V8 and a 86' D300 new seals and yokes
Cases I got for free, I also traded some old spare 231's and a D300 and $300 for the doubler pieces which include a new 23spline billet shaft,.250 spacer and welding/hardware. With stock dana300 yokes it was 1" shorter than a stock 231, with 231 yokes,on stock outputs it's off by about 1/4". gearing is stock in both cases so overall of 7.13:1
http://i80.photobucket.com/albums/j200/redder22/DSCF1647.jpg
http://i80.photobucket.com/albums/j200/redder22/DSCF1645.jpg

i am doing 231/to non flipped 300, anyone have pics of how the are supporting cases, i dont want all that weight hanging off the back of the tranny.

Box 4 Rocks, 23 spline input. stock ratios in both cases. second D300 (cracked the first one). Leaf spring bushing style mount on the back of the D300 to support the weight.

http://i170.photobucket.com/albums/u277/gravesdiggerxj/Krazy%20Fabworks/TJ/100_1756.jpg

http://i170.photobucket.com/albums/u277/gravesdiggerxj/Krazy%20Fabworks/TJ/100_1757.jpg

http://i170.photobucket.com/albums/u277/gravesdiggerxj/Krazy%20Fabworks/TJ/100_1758.jpg

Box 4 Rocks, 23 spline input. stock ratios in both cases. second D300 (cracked the first one). Leaf spring bushing style mount on the back of the D300 to support the weight.

http://i170.photobucket.com/albums/u277/gravesdiggerxj/Krazy%20Fabworks/TJ/100_1756.jpg

http://i170.photobucket.com/albums/u277/gravesdiggerxj/Krazy%20Fabworks/TJ/100_1757.jpg

http://i170.photobucket.com/albums/u277/gravesdiggerxj/Krazy%20Fabworks/TJ/100_1758.jpg

some pics of how you guys are mounting the bushing to the dana 300 or np 231 would be very appreciated, and super helpfull, thx

Some starter pics of my GM203 to CJ D300 I'm making. The adaptor is at my machinest getting faced and I just got the midshaft back for moses yestarday so it's more advanced the it looks in the pics.
Started by using my D300 clocking ring and a chunk of 1" plate.
End cost will be under 250.00 as the tranny, 203 and steel was fre and I already had the Clocking ring and d300. Shaft work was the costly part and added parts for shifters.
http://i66.photobucket.com/albums/h251/JK_Motorsports/2009%20Build/DSC_0021.jpg
http://i66.photobucket.com/albums/h251/JK_Motorsports/2009%20Build/DSC_0236.jpg
http://i66.photobucket.com/albums/h251/JK_Motorsports/2009%20Build/DSC_0237.jpg
http://i66.photobucket.com/albums/h251/JK_Motorsports/2009%20Build/DSC_0239.jpg

ready to put my 231/300 doubler in the xj and had a few questions.
I have seen people recomend running atf in the cases, why not run atf in 231 like it was meant to and gear oil in 300 like it was meant to? does the 300 not have a sealed input bearing? i think it would have to as they came behind autos which would leak atf in gear oil and vise versa. please correct me (more like flame me) if im wrong.
I was thinking of running a lucas/atf mix in 231 and lucas/gear oil in the 300, yay or nay?

I guess I need to get a red star to post up some pics of my setup.

I am running the Box4Rocks 231/231. I flipped the front case, and clocked the rear as flat as possible. I got a set of used cable shifters from a buddy, and they look identical to Brass Munkey's. Woody also helped/did a flat skid on my ride. ONly issue I have had is it leaks or blows atf out.



Pics can be found on my webshots page around page 10

http://community.webshots.com/user/cj7xjmj


Of course it is under the knife again for a quick full width swap:evil:

am running a 231 with a D300. Dand D adapter. 91 XJ

there is no place to put the speedo, and lately the check engine light is going on, and my auto trans is getting bad codes and acting up. At first I had no problems, but after about 500 road miles and a bout 50 trail miles the codes kept coming up.

What did you guys do about your speedo plug and the other plug? another question that I have is on the oil level. Should the sight tubes be filled to the center , or a little higher. After I raised my level to 1 inch above center, I wound up having to replace a couple seals.

How about linkage. I would really like to have something that clicks into place. Mine (home-made) is kind of floating around for when I am in positions I want to be for the axle shift twin sticks.

MY buddy Woody had BrassMunKy's cable shifters, and he modded a 231 stock linkage to work on the cable ends. It is a feel kinda shifter that has positive clicks when you go into gear.

DID you put a vent on your case.. that might have been why YOU blew the seals

It is vented. any input on how high to fill it using the sight hoses?

the D300 and the NP231 share a similar VSS port.

they should swap right in.

Add the correct speedo gear, and you're good to go.:D

So I am getting Check Engine Codes because my speedo plug is not plugged in to anything since the sending end is no longer on the 231 case. Does anyone know how to wire the connectors so the circuit appears complete and stops sending the Engine Code? I am using a NP231 and a
D300 with a D and D adapter. Not that it matters, andy disconnected speedo would be the same.

So I am getting Check Engine Codes because my speedo plug is not plugged in to anything since the sending end is no longer on the 231 case. Does anyone know how to wire the connectors so the circuit appears complete and stops sending the Engine Code? I am using a NP231 and a
D300 with a D and D adapter. Not that it matters, andy disconnected speedo would be the same.

You can make it work. You will need a electronic sending unit for the d300 and a recalibraton box. It is not cheap, about 200 or so, but it would give you a working speedo and no code. I don't think you can just wire it bc the speedo works on pulses.

Anyone of you guys want to take measurements of these componets for me?

Im not trying to start making these and make money, I just wish to machine one set for myself.

Im going to run a AX15 with the 231 doubler and then the 300 as the case.

I need measurements of the thickness of the plates. I have the two cases Im just trying to save a little time with my thinking cap on. How about the main holes in the plates for the shafts? My only real concern is for the small mainshaft. Im going to have to try and buy that or have it made up.

Im trying to build my engine and axles so Im trying to save as much money as possible without skimping.

It is vented. any input on how high to fill it using the sight hoses?

Fill the case up to what factory reccomends.

Dana 300: 4 pints (1.9 liters) SAE 85W-90 gear

NP231: Like 2 quarts ATF.

Personally I would fill them to these levels and then add if you feel the need. If they are clocked you might want to add some fluid, you are also going to have to check the levels becasue they will piss out of the vent.


NOW does anyone want to tell me what thickness their plates are made of? Otherwise Im just going to walk up to the aluminum pile and pick what I think looks nice. Someone said 7/8"??

For those with a flipped 231 box4rocks, what are you doing for shift linkage to the 231 ? Pics if you got em, PLEASE
!:confused:

http://sphotos.ak.fbcdn.net/hphotos-ak-snc4/hs681.snc4/62170_1495130611323_1025802758_31155353_5087623_n. jpg

http://sphotos.ak.fbcdn.net/hphotos-ak-ash2/hs366.ash2/64450_1496730811327_1025802758_31159489_5641560_n. jpg

http://sphotos.ak.fbcdn.net/hphotos-ak-snc4/hs732.snc4/65289_1496731771351_1025802758_31159495_2104228_n. jpg

Ok Thanks. Thats the Dana 300 linkage... I can see the 231 lever in your pics but nothing is attached to it ?

anyone have any linkage shots for a flipped 231 ?

pretty sure the 231 is still right side up, you just flip the d300 to get the output on the drivers side

pretty sure the 231 is still right side up, you just flip the d300 to get the output on the drivers side

The 231 has to be flipped because the front output for the D300 won't clear the part of the case that is left after you cut it. If you do a custom doubler half and tweak it, you might be able to clear it, but I doubt it.

Ok Thanks. Thats the Dana 300 linkage... I can see the 231 lever in your pics but nothing is attached to it ?

anyone have any linkage shots for a flipped 231 ?

Here, Im answering my question. :flipoff2:
This 231 isnt flipped in this pic but you can use your imagination.

not my pic

http://img838.imageshack.us/img838/8931/p8200039w.jpg



pretty sure the 231 is still right side up, you just flip the d300 to get the output on the drivers side

yeah.... um no. :p

So is anything special required to "flip" the 300 to d-side drop when using the D/D kit? Do I need a "flip" ring or can I just flip it over when attaching it to the back of the 231?