AX-15 with all wheel drive

[FARMER]

Will an all wheel drive out of say a ZJ bolt up to an AX-15. If not what would be the options for a 4.0 with a manual and all wheel drive?

[sly-jeeper]

my personal choice would be a np 242 it gives you the option of two, all wheel, 4 hi, and 4 low all in one very reliable unit with no viscous coupler...in all wheel drive it acts as an open differential between the front and back axles and drives amazing in the snow

[SilverXJ]

A NP249 out of a ZJ will bolt up. However, it is a pos and your best advised to stay away from it. The viscous coupler likes to lock up. Garbage case. A NP247 out of a WJ will bolt up,. but it doesn't have the speedo function.

My vote goes to a NP242 as well. I have one in my XJ and am looking for a good used one to replace the 249 in my ZJ.

[FARMER]

Thanks guys, how would the 242 do on dry pavement? I'm looking at building a Jeep street rod and don't want to do trial and error to get it to work right.

[SilverXJ]

Very well. All 3 of my XJs have been the 242. I love it. 2wd, 4x4 fulltime, 4x4 part time w/ shafts locker and 4 low. Works great all around. You can even use it in the wet which I do just so the rear won't slip on some bad pavement. All 3 of my ZJs have had the 249 and I have hated every moment with they because that POS coupler locks with age and the replacements aren't much better.

[sly-jeeper]

the 242 when in full time mode is essentially a open differential between front and back...i beat the tar out of mine with over 200,000mi on it and when it broke it was only a stretched chain...it was easy to fix.make sure all your tires are exactly the same brand, size, air pressure, and wear along with same gearing front to rear it goes along ways in taking stress off the t-case...you can always just shift it into two wheel mode if you don't need the all wheel.it should hold up fine on pavement if you treat it right

[jeepxj3]

Very well. All 3 of my XJs have been the 242. I love it. 2wd, 4x4 fulltime, 4x4 part time w/ shafts locker and 4 low. Works great all around. You can even use it in the wet which I do just so the rear won't slip on some bad pavement. All 3 of my ZJs have had the 249 and I have hated every moment with they because that POS coupler locks with age and the replacements aren't much better.

Nice, 3 Xjs and 3 ZJs. And 242s, that's rare enough.

[embs2001]

It seems like the 242 in Full-time would be good up until you lost traction. Then all the power will go to one tire, likely the front right or left (unless front locker). Your awd jeep will turn into a one wheel drive, front wheel drive.

The 247/249 with a LSD rear diff will at least spin 3 tires if the viscous coupler was in good shape. I wish the 247/249 could switch between 2wd and awd but I believe it wears out the coupler if it is not splitting the power. (for example removing a front drive shaft)

I just launch in 4 part time!
Let me know if anyone has different experience.

[embs2001]

I have always wondered how a 247/249 tc with front and rear truetracs and globs of power would handle in a lowered XJ/MJ.

[SilverXJ]

It seems like the 242 in Full-time would be good up until you lost traction. Then all the power will go to one tire, likely the front right or left (unless front locker). Your awd jeep will turn into a one wheel drive, front wheel drive.

That is not exactly how it works. When you use the full time more for its intended purposes (lose surface, but not needing part time) it does quite well. In normal driving there will be none of this so called 1 wheel drive that people propose. It just does not happen. Even off road on a fire road it doesn't work like that. There have been situation where I lifted one tire and the full time never lost traction. If you get past that point you shouldn't be in full time any how and with the 242 you have the option of going into part time when needed. Personally I find the part time option quite useless. If I in a situation with the much slip I will be in 4 low.

The 247/249 with a LSD rear diff will at least spin 3 tires if the viscous coupler was in good shape. I wish the 247/249 could switch between 2wd and awd but I believe it wears out the coupler if it is not splitting the power. (for example removing a front drive shaft)

The 249 is a POS any way you shake it. Ever the replacement VCs are crap and often fail in 20k miles. However, in 1996(iirc) they changed the way the VC engages and it isn't a problem running w/o a front shaft. The 247 has its own problems but isn't as bad as a 249. Besides its stock issues the problem with 247 is that it doesn't have the correct out put shaft and housing for the speedo gear. Its no simple matter to swap though. It is however, a much better case than the 249 and if you want full time awd then a hybrid case is a good option.

[embs2001]

That is not exactly how it works. When you use the full time more for its intended purposes (lose surface, but not needing part time) it does quite well. In normal driving there will be none of this so called 1 wheel drive that people propose. It just does not happen. Even off road on a fire road it doesn't work like that. There have been situation where I lifted one tire and the full time never lost traction. If you get past that point you shouldn't be in full time any how and with the 242 you have the option of going into part time when needed. Personally I find the part time option quite useless. If I in a situation with the much slip I will be in 4 low.

::Thats good to hear. I always thought jeep engineers would have been smarter than that. That was just how I saw it described in other forums on the topic.

Yea I just remembered after posting that the 247 does not use a VC. What would be cool, (and likely expensive) would be to use a system like some of the awd drift cars use. They have a clutch somewhere along the drive line that can disengage the front drive with the pull of a lever.

ken block uses one!
https://www.youtube.com/watch?v=dKBICDja6Sg 4 minutes in.

[SilverXJ]

What would be cool, (and likely expensive) would be to use a system like some of the awd drift cars use. They have a clutch somewhere along the drive line that can disengage the front drive with the pull of a lever.

I fail to see how that would be useful except for something like Ken block does. I have never been in a situation where I wish I could disengage the front axle and lock the rear wheels up.

[embs2001]

I don't want to lock up the rear wheels. Just not be stuck in awd.

Burnouts, fishtail, initiate a slide, you know the fun stuff. I would have said donuts but awd donuts are better.

[embs2001]

Obviously the 242 is the best practical choice if you want to still have 2wd, but I feel a good 247 unit would have superior awd.

[amceaglesx4]

242 all day. Stronger than the 231. Pleople will argue that one but they are just wrong lol.