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to double or not to double

BenDiesel

BenDiesel

NAXJA Forum User
Location
lynnwood washington
so i been looking into d300 tech. got one already and have seen a few names pop up quite a bit. first has been stak and the other dd machine.

so i was wondering how many people run a fliped stock d300 case? any leaking issues? do you think the money would be well worth a drivers drop replace a case? if i do run just the d300 i have to find a new input shaft. i believe my 89 is 21 spline and d300 is 23. stak makes a new shaft and adapter kit for the older xj.

the other thing i have been considering is doing a 231 low box infront of the d300. i am running a aw4 so kinda worried that it might be too low for me. i do plan running a set of radesigns shifters and a lockup switch.

so what do you guys think

low range box 4 rocks
http://pirate4x4.com/forum/showthread.php?t=696803

stak replace a case
http://www.stak4x4.com/Dana_300/replace-a-case.htm

stak adapter and input shaft
http://www.stak4x4.com/Dana_300/d300_aw4.htm
 
i plan on running the box 4 rocks. mainly because i already have a d300 and it'll be cheaper than buying a sye and 4 to 1 gears for the 231. i am a little concerned about it being geared too low. but you don't always need the double low. the low range for the d300 is 2.62 i think and the np231 is 2.72. either way they are close enough so if you only run one it'll be just like a stock case. only you will have 2low with the d300. if you twin stick it
 
Ya I was thi.nking the same thing till I realised that the doubler and d300 is 19 7/8 inches long (long output I think) which I think is longer then a stock 231. Just sayin. In any event I want it for thwe cool factor. But it leads to more dificult shifting problems.
 
I maybe able to shed some light on this i have done a ton of research on it and am in the middle of flipping a 300 in my xj

With the dana 300 the oil leak on a flipped 300 it usually comes from the shift shaft seals. You can replace them with new ones with one seal per shaft, or you can replace it with 2 seals per shaft which is what a lot of people do. It is quite simple to put 2 in the first set of seals sit flush with the housing. The second one butts up to the first and there is a groove in the retainer which allows it to sit flush like it would stock with 1 seal. For shifters i got the northwest fab ones http://www.northwestfab.com/Shifters.html It took a while to get them but they are awesome quality. If you want to run just the dana 300 to the aw4 novak along with a few others make a 21 spline input shaft for the 300. Also you can use 2 231 front yokes to swap it to cv shafts http://www.northwestfab.com/Shifters.html

As for the doubler we did one not too long ago in a yj using the mad rooster kit iirc. It was a stout setup but in low low it was pretty low put it had an ax15 in it which allowed better gear selection. You also need to make a brace for the back of the 300 to support it.
 
As for the doubler, it kind of depends on what kind of wheeling you do, and what gears you have in the diffs. Do you find yourself needing that extra low on the trail much?
Running the single case would be so much simpler, I would probably nudge you that way, and maybe run a 4:1 if you do more crawling. Even with 2:72, guys in autos with like 4.88s in the diffs seem to be quite happy with it for their low-speed needs.
That said, I have a doubler (basically) via a 4sp atlas and I love it - but I have an AX15. I think it takes a lot for it to be worth it in an auto, but I have not first hand experience with one.

The 7.1 compound low would be cool, but I think it tends to be an advantage when running really technical stuff with large tires (38+). At least I would think so with the auto. I have been really suprised how often I use the compound low on mine.
 
Last edited:
Hey thanks for the input guys. Any one know of a write up on the double seal of the shifter forks? How well did just the d300 fit in the xj (I have herd of some requireing some hammer tuning to the trans tunnel)
I wonder if the shifter location on the d300 will lign up with the factory hole. If so I will probably use this kit or something like it. http://www.pirate4x4.com/forum/showthread.php?t=505924 . If not ill prob do a under reverse cable shifter of my own design :)

Thanks for the input guys
 
for the double seal get 4 stock seals undo the 1/2" bolt on the seal housing looks like an 8. put first seal on will be flush with the lip put second seal on bolt back together

i had to trim the old shifter housing to make it fit a little hammering on the tunnel
 
raze1287 said:
I maybe able to shed some light on this i have done a ton of research on it and am in the middle of flipping a 300 in my xj

With the dana 300 the oil leak on a flipped 300 it usually comes from the shift shaft seals. You can replace them with new ones with one seal per shaft, or you can replace it with 2 seals per shaft which is what a lot of people do. It is quite simple to put 2 in the first set of seals sit flush with the housing. The second one butts up to the first and there is a groove in the retainer which allows it to sit flush like it would stock with 1 seal. For shifters i got the northwest fab ones http://www.northwestfab.com/Shifters.html It took a while to get them but they are awesome quality. If you want to run just the dana 300 to the aw4 novak along with a few others make a 21 spline input shaft for the 300. Also you can use 2 231 front yokes to swap it to cv shafts http://www.northwestfab.com/Shifters.html

As for the doubler we did one not too long ago in a yj using the mad rooster kit iirc. It was a stout setup but in low low it was pretty low put it had an ax15 in it which allowed better gear selection. You also need to make a brace for the back of the 300 to support it.
Click to expand...

I also am looking at flippin a d300 and putting it in. Are the shifters worth the $300?
 
Doose-doe said:
I also am looking at flippin a d300 and putting it in. Are the shifters worth the $300?
Click to expand...

It is a really nice setup comes with everything easy to adjust i was impressed. Everything on it is easy to setup pretty simple to put together i would recommend them. Ill post up some pics tomorrow since i need to pull my 300 out.

Ill also post some pics of the double seal ordeal since my other 300 is apart
 
Thanks for the input guys. I'm probably not going to go with a doubler. But deff gona flip the 300

Dose any one know if the shifter mount lines up near the hole for the factory shifter?
 
Last edited:
BenDiesel said:
i am running a aw4 so kinda worried that it might be too low for me.
Click to expand...
No such thing
BenDiesel said:
Thanks for the input guys. I'm probably not going to go with a doubler. But deff gona flip the 300

Dose any one know if the shifter mount lines up near the hole for the factory shifter?
Click to expand...
You'd probably break your axles with a doubler, anyway.

I'm going to go ahead and say that they're close but I think you'll still need to cut the floor to make it all work.

I won't be buying shifters for mine, when it comes time to cross that bridge. Depending on your level of fab skills and tools you have available, you may decide that buying the shifters for $300 is the best option.

Flipping the 300 and using a double seal is sort of hokey, in my opinion. Do it right and make/buy a real flip kit that relocates the shifters to the other side of the case.
 
asp said:
No such thing

You'd probably break your axles with a doubler, anyway.

I'm going to go ahead and say that they're close but I think you'll still need to cut the floor to make it all work.

I won't be buying shifters for mine, when it comes time to cross that bridge. Depending on your level of fab skills and tools you have available, you may decide that buying the shifters for $300 is the best option.

Flipping the 300 and using a double seal is sort of hokey, in my opinion. Do it right and make/buy a real flip kit that relocates the shifters to the other side of the case.
Click to expand...

doubler has a lot of torque coming out of it so yea axle breakage could happen

yes from what it looks like you do need to cut the floor about an inch or two. I had to buy the shifters i got the skills but lack the time. Plenty of people run the double seals with no issues.

when i get closer to finished/ more time possibly this weekend as long as im not out plowing ill take some good pics of it all
 
I've got a doubler clocked flat in a comanche. I couldn't get it to work with a 1 piece driveline so I run a two piece up front. The gearing options are nice to have though. It seems nice and hasn't let me down yet (there is always next week :cheers: ).
 
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