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Durango box mod no good

D

dan89XJ

NAXJA Forum User
Location
Oregon
Ok, I got a 99 durango box to swap out my old box with. I searched the internet all over and got all the "information" about the upgrade. Here are the Facts.. a 99 durango box(non plow) input shaft only turns approx 2.75 times. While the output shaft will only turn less than 45 degrees. 89 XJ stock box input shaft turns approx 3.5 times, and output shafts turns closer to 45 degrees. So this is why people want to modify the durango box to gain more output shaft turning to match the stock output shaft turning capabilities. I went ahead and spent my day modifying this durango box so I can have full turning capabilities as my stock box would have. The mods I did were remove the spacer that the worm shaft rides on in side the bottom of input shaft cylinder of the gear box. Also grinded down the tabs off the aluminum front cap of the gear box which would allow the piston to travel slightly further. And boy did I have fun getting this thing back together.. while originally following a write up on naxja.org, someone wrote to put the balls back in the piston prior to installing the piston into the gear box housing using some roll up paper method. This did not work. You must pull the output shaft and install the balls after the worm gear and input shaft assembly has been installed back in. This was no problem at all to do. Thanks a write up I found on pirate4x4.com with this information on how to rebuild a box.

So after all is done and assembled.. the results were not satisfying for me. I did gain more travel. The modified durango box now has approx 3.25 input shaft turns. Output shaft now turns slightly more ! but still less than my stock XJ box ! I compared the boxes next to eachother and made marks and visually compared how much the output shaft turns on each box. Its a few degrees less.. maybe 5-10 degrees. So I think I'm gonna put my stock box back in. There is nothing to be gained with this durango box for me.
 
best thing you can do is put a camaro/firebird box "quick ratio" from a 1990 or so moel.i have one and it fits perfect no mods!
http://www.jeepforum.com/forum/f11/going-junkyard-611407/
4 th down...
also
PART NUMBERS FOR GM REPLACEMENT BOXES

From Magazine articles82-86 Z/28, TA 12. to 1 ratio. 783897
83-86 Monte Carlo SS with HD susp, 83-84 Hurst Olds, Regal with FE2 FE3, 86 Grand Prix with touring pkg. 12.to 1 7843135
84-up firebird & TA with 16" wheels (N96), 85-86 IROC (FE2 16" wheels), 86 firebird all V8 Stiffer valve than above - 7843512
12.7 TO 1 BOXES

psbox_chart.jpg
 
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hmm.. thats interesting. I had a ws6 box out of a 84 TA. I sold it along with a malibu as extra parts after I got bit by the jeep bug. Yeah, I remember that box.. it was quick. Interesting chart you posted as it lists travel in degrees.
 
dan89XJ said:
Ok, I got a 99 durango box to swap out my old box with. I searched the internet all over and got all the "information" about the upgrade. Here are the Facts.. a 99 durango box(non plow) input shaft only turns approx 2.75 times. While the output shaft will only turn less than 45 degrees. 89 XJ stock box input shaft turns approx 3.5 times, and output shafts turns closer to 45 degrees. So this is why people want to modify the durango box to gain more output shaft turning to match the stock output shaft turning capabilities. I went ahead and spent my day modifying this durango box so I can have full turning capabilities as my stock box would have. The mods I did were remove the spacer that the worm shaft rides on in side the bottom of input shaft cylinder of the gear box. Also grinded down the tabs off the aluminum front cap of the gear box which would allow the piston to travel slightly further. And boy did I have fun getting this thing back together.. while originally following a write up on naxja.org, someone wrote to put the balls back in the piston prior to installing the piston into the gear box housing using some roll up paper method. This did not work. You must pull the output shaft and install the balls after the worm gear and input shaft assembly has been installed back in. This was no problem at all to do. Thanks a write up I found on pirate4x4.com with this information on how to rebuild a box.

So after all is done and assembled.. the results were not satisfying for me. I did gain more travel. The modified durango box now has approx 3.25 input shaft turns. Output shaft now turns slightly more ! but still less than my stock XJ box ! I compared the boxes next to eachother and made marks and visually compared how much the output shaft turns on each box. Its a few degrees less.. maybe 5-10 degrees. So I think I'm gonna put my stock box back in. There is nothing to be gained with this durango box for me.
Click to expand...
You can regain the lost travel by installing a slightly longer pitman arm.
 
dan89XJ said:
I did hear about doing that. What arm would be good ? I hear a WJ arm is longer, do they fit ?
Click to expand...
I don't know which one fits but there are an awful lot of cars that use the same design steering box. It shouldn't take long at the junkyard to find a pitman arm a little longer than ours.
 
The point of the durango box is that it is larger and gives more power assist. Also it is a fixed ratio vs the XJ's variable. It is a very mod.
 
Ok.. you guys made a good point. So, today I threw the box in and took her for a spin. With the stock pitman.. I'll have to research and figure out what pitman arm to get to gain my lock to lock turning back. It did fine.. made some noises at first, some kind of popping when I turned full right. Then went away some. It turns pretty good when going down the road, but if the rpms drop low enough and I'm making a big turn, its hard to turn the wheel and I have to muscle it. Seems like 1,000 rpm and up its easy.. but if it drops below that turning is harder.

So.. I'm thinking I need a diffrent pump or a PSC pully ? I hear guys swap in a certain ZJ pump. Also heard about a smaller pulley made by PSC. I could not find this pulley on their website.
 
Alrighty.. bigger pump = more volume ? More PSI ? a underdrive pulley would simulate both of this right ?

Whats the deal with the unique ZJ pump ? Physically its the same size isnt it ?
 
I run the 2001 Grand Cherokee V8 pump. The GC in that year model utilizes a hydraulic cooling fan and both it and the PS run off the same high output pump. It helps a lot but at low rpms with my hydroassist I still use the smaller pulley.
 
I read about the drilling mod.. but cant figure if its a good or bad mod.

I also found out about the 01-04 WJ 4.7 pump.. but cant figure out if its bolt on for a RENIX 4.0.

Also, the PSC pulley sounds like a good way to go.. but cant figure out if it fits my RENIX 4.0. They list it to fit 96 XJ's.

So.. now I gotta figure out which to do first. I'm leaning towards the pump, I think I can pick one up for $50 at a JY. But then its a JY one.. dont know of mileage or if it's performing like it should.. which would lead me to do other mods.
 
I've been pleased with my YJ box. It's fixed-rate like the Durango w/ plow (and is not variable-rate like the XJ/ZJ), has a 4th hole for extra strength whenever I get around to using it (same as XJ until then), and it works fine with the stock pump.
 
Cool.. I'm not sure if the drango box without plow is fixed or variable ratio. But.. I remember reading somewhere that a variable ratio box just goes from 13:1 to 15:1.. and its 15:1 at a remaining part of a turn.
 
Wouldn't a long arm reduce the extra leverage gained by using the dingo box.
I think it would be better to find a big piston box with the right or better swing in the first place.
=======================================
Whats the deal with the unique ZJ pump ? Physically its the same size isnt it ?
=====================================
It uses a higher re-leaf value but puts out the same volume at any given RPM.

======================================================
Durango boxes have a larger piston so they need more fluid pressure, aka bigger pump
=====================================================
They don't NEED more pressure. They ((((MAY))) need more volume. NOT the same thing. Unless you are a sissy with really big tires. :) :) :) THAT is only if your stock pump can't keep up in volume. You could tell this by the PS cutting out when you try turnning the wheels very fast. But when turned normally all is well.
Often a VERY tired pump with 200k+ miles on it Not putting out near what it did when new (volume or presser). Is replaced my a NEW ZJ V8 Hiper whatever. The low volume problem goes away and the V8 pump is said to put out more(((( volume)))) A amount of volume IS needed at a given presser for all to go well but they are not the same thing.
 
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Hmm.. I drove the jeep again today, and it did better. I think the pump may be tired.. the rig has 235,000 miles on it.. and I'm guessing its the stock pump. It does fine, but after a drive, it starts to act up. So.. I'm thinking of getting a zj pump or a reman stock pump. So, whats the best pump to go with ? ZJ, WJ or a stock XJ ?
 
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