Hack and Tap WARNING

[ROCKREADYXJ]

I have never recomended using one of theese they are not a smart idea.

What is it? Its a np231j found in several model select track Jeeps. On the back it is the very famous Hack and Tap kit this is what could happen. The shaft went out of balance snaped the output shaft and thats what you get.

http://img.photobucket.com/albums/v228/ROCKREADYXJ/hackandtap.jpg

[magoo117]

damn Joe,that one looks worse than mine!!!

[XEON]

Thats exactly why I spent the extra penny to get the AA HD SYE kit :)

Thanks for the scaryness... :D Now I am happy I went the extra mile :)

[badzook]

Hey Joe,

Now you have an excuse to replace it with an Atlas unit. :lol:

I was thinking about this and I can't help but wonder if there isn't some reason for all of that destruction.

I don't like the hack & tap either it places a lot of stress out side the TC housing along with alot of weight on the end of that output shaft.

I have some questions about this episode... ( Meant to be taken out of curiosity and not to poke any fun at you )....I'm not an engineer or an expert on the subject but am interested in seeking a reason for this failure.

Did it happen while crusing down the highway or when climbing rocks?

Did you have any warning like bad vibes?

Is this the TC on the red XJ you have pictured that rolled over??

If it is a couple things come to mind on this.

1) Those tires are really big and cause alot of stress on the driveline.

2) There is like 6" of lift causing some very steep DS Angles and stress on the TC

3) Was the TC a really high mileage unit and worn out?

4) If you have lockers in both diffs they cause alot of stress where the torque joins up at the TC. I think you could call it feedback torque.

5) If you had vibrations maybe your bearings were wiped out prior to the damage causing the misalignment of gears and shafts.

6) The transfer case wasn't designed to carry the extra weight of a CV joint hanging way out back of the TC.

I'm just thinking that for a daily driver that does some light duty offroading with a 3" or so lift with open diffs and say 32 or 33" Tires, the Hack & Tap or Short Replacement Shaft kit should work fine, because you are not exceeding the capabilities the TC was designed for.

When you get into some hardcore rockin' some serious and expensive
mods become necessary.

One more question... how is the Unibody Frame holding up on your XJ?
Besides the steering box area being a weakpoint, are there any other areas you've experienced trouble with??

These are questions that are always lurking around in my mind
:?: :?: and it helps to hear input from someone who has been there and done that...


Thanks for your input .

ttyl
badzook

[magoo117]

The red Chero that rolled is Joe's,that has an Atlas in it.I dont know who's the 231 is,I'm guessin' one of his customers.

[MikeN]

What is a Hack and Tap Kit?

[XEON]

What is a Hack and Tap Kit?

THats instead of changin the output shaft to a smaller one. Basically you just hack some parts inside of the t-case and then added a little flang for the cv shaft to bolt to. They are the low cost SYE.

[ROCKREADYXJ]

Hey Joe,

Now you have an excuse to replace it with an Atlas unit. :lol:



OK I will start from the begining I have an atlas already.

This is a customers truck.

This did happen while driving down the road. I dont think there were vibes to give warning. If there was he did not notice it.

No it is not the xj in the pictures.

1) 37x12.50x15
2)There is 8 inches of lift and the angles on my truck are not that bad at all
3)He had 60k on it
4)Not a concern it was in 2wd unlocked in the rear
5)I pulled it apart the bearings were fine
6)that is true to a point the case can handle it its the weak output shaft that cant handle the added tourqe.


I would not recomend that Hack and Tap. I don't care what lift or tires you have. its the rear output shaft that is half the size of the AA SYE shaft.

I will see if I can find an old shaf to campare to the newone so you can see the difference.

My Unibody frame is fine no problems at all even with th roof off. I would also reenforce the track bar bracket. Deffinitlly the steering box. I riped mine out of the frame had to bebuild the frame w/ some 5/16 and 1/4 plate.

You are more than welcom to come by and check it out if it would help.

Joe

[badzook]

Joe,

Thanks for the info. I've been wondering about that pic and the cause of the damage.

Apparently the shaft is the problem in this case. It's amazing the amount of damage it can do...

I was pondering which kit to install for a few weeks and finally went with the AA sye kit. Mine was from Tom Woods, I think it's the same as the AA Sye kit (It's a short shaft replacement) ..

I didn't like the idea of the Hack & Tap kit either.. The shaft is still too long when finished. The weight of the CV unit causes a great deal of stress on the back end of that shaft.

BTW incase anybody else is considering this type of install...It's not all that difficult. Just keep good track of where all the components go. You DON'T have to remove the FRONT DS and YOKE to install this shaft. There are circlips on the gears at the back of the TC allowing the gears to slide out from the rear. And you DON'T need a press to remove or install these parts....

I think it was worth the extra money and time... and it wasn't that big of a deal to install either...If you're mechanically inclined and have a good pair of spring clip pliers. You're set.

There's really no reason to do the H&T as it's not that much more labor intensive. Maybe an hour or two more time...


Happy Holidays :)
ttyl
badzook

[ROCKREADYXJ]

I wouldn't say it's that easy there are things that you should check before re assembling. I would suggest you take out the front yoke when you are installing this kit it is a good time to replace the in put seal. You can also check the bearings and chain for wear. I pull the whole case apart down to the planetary and clean and in spect in the parts washer. It does not take that much longer. When I am complete I am confident that every thing is in working order. I also have the parts in stock to replace them with if they are bad. I sell the AA

What kit did you get from tom the AA or the JB?

[badzook]

Tom builds the kit inhouse..
He takes your core shortens it and then machines a spline into the end of the shorter shaft and machines the threads into the end of the shaft.. He supplies the yoke with hardware and a rear output housing assembly complete with a new bearing and seal.
badzook

[ROCKREADYXJ]

Yeah I have seen that one I would advise agints it. it is basically the same as a hack and tap kit. It uses a stock shaft just cut down.

Go for the AA or the JB.

[badzook]

The Tom Woods kit appears to be exactly the same as the JB kit. I was just checking out their website. The shaft TW provides is considerably shorter than stock. Nothing like the H & T ..
badzook

[ROCKREADYXJ]

I did a couple of his kits they use the factory shaft thats why there is a core if you don't send back the output houseing and shaft. the JB and the AA give you new out put shafts the TW is a factory shaft not as strong.