2 to 4 wheeldrive

[Eliminator89]

Ok, thinking of converting to 4 wheeldrive.

 

I don't know the systems on the MJ/XJs very well. I hear of vacuum disconnect front axles and non-disconnect axles. As I understand things, the vac axles are high-pinion and the nons are low-pinion. The vac axles are in earlier trucks and the nons are in later trucks. The non have larger u-joints on the axles and the vacs have smaller joints.

 

So, the nons are a bit stronger but you lose the high-pinion advantage. That shouldn't be a problem as I will not be lifting the MJ.

 

I also would like full-time but hear the 242 is not that strong. I have a 219 in the shed. I also have a 208 (I know, not full-time) in the shed also. Both are from behind 727s (Jeeps) and I have an AX15 in the MJ.

 

So, it seems it would be easier for me to get a 4 wheeldrive AX15 (external slave this time, no more $700 slave replacements) and a 231 and forget the full-time. But I would REALLY like to have full-time. The truck will see mostly street use with an occasional trail ride (no level 3 or 4 trails).

 

I've had two full-time FSJs (one '79 BW1339 and one '80 NP219) and really like that for winters here in Minnesota. I thought the BW better but since they are passenger drop, and rebuild parts non-extistant, thats out.

 

I have read that the D300 adapter from a CJ will fit the 219 or 208 to the tranny.

 

Did the 242 come behind the AX15? If not, can I put one there anyway? Taking the easy way has never been my style but I'm getting older and lazier...

 

You guys don't mind giving opinions do you? :roll:

[JeepcoMJ]

So, it seems it would be easier for me to get a 4 wheeldrive AX15 (external slave this time, no more $700 slave replacements) and a 231 and forget the full-time. But I would REALLY like to have full-time. The truck will see mostly street use with an occasional trail ride (no level 3 or 4 trails).

 

 

first, to switch to 4wd, you will need the front axle (obviously), front driveshaft, 4wd tranny (easier and more effective than converting 2wd tranny to 4wd), the 4wd selector, and linkages.

 

now, on the front axles, I believe you are very correct, except that some non-CAD axles had CV joints as well. stay away from those.

 

get the non-CAD front axle, it eliminates the sometimes-faulty vacuum system. then DEFINITELY get a 4wd tranny and t-case (you need the ax15 with your engine option i believe.). the best bet is to simply convert it at first, and opt to change out to fulltime at a later date. I believe you can fulltime it with little mods...but don't quote me on that.

 

any input on specific tcase advantages and disadvantages from anyone else?

[Eliminator89]

"some non-CAD axles had CV joints as well"

 

CV joints at the knuckles or the driveshaft? CAD mean Center Axle Disconnect?

 

I'm planning to visit a Jeep oriented salvage yard tomorrow and get a look at things, take some pics, talk prices.

[dfreeman616]

"some non-CAD axles had CV joints as well"

 

CV joints at the knuckles or the driveshaft? CAD mean Center Axle Disconnect?

 

I'm planning to visit a Jeep oriented salvage yard tomorrow and get a look at things, take some pics, talk prices.

 

at knuckles, and yes on the cad (vac disco axle)

[JeepcoMJ]

thanks dfree...

[Crash_AF]

Been through this exact swap with a 242...

 

You need a 242 from a later XJ with 23 spline input to bolt to the AX-15, any from after 91 I believe will work.

 

There are three non-disco axles:

Most 84-86 Selec-trac had CV joint style front axleshafts

87-91 Selec-trac had high pinion and 260 u-joint axleshafts

all 91-99 had high pinion non disco and around 93 upgraded to the stronger 297 axleshaft ujoint

00-01 used TJ low pinion non disconnect axles with the stronger 297 ujoints

 

Disconnect axles were pretty much the same throughout their use.

 

The only modification to the above is that ALL ABS equipped D30s had the 297 axleshaft joints

 

Shafts for non-disco axles will interchange, so if you get an earlier axle, you can pick up a set of later shafts to swap for the 297 joints

 

In addition to the above list, you will also have to get the shift linkage for the transfer case from a donor and make sure you get all the pivots from a manual transmission truck, automatic pivots won't work (Ask me how I know :D ). You need the transmission pivot, bellcrank linkage assembly and the transmission tunnel pivot. Your rear driveshaft will also have to be custom made or from a 4wd MJ.

 

The 242 is a great transfer case and will hold up to everything you want to do. I have a 242 in the MJ in my sig behind a AX-15 and it has held up with no reliability problems at all.

 

If you have any other questions, feel free to ask and I'll try to explain details better.

 

Later,

Joe

[mjeff87]

yup, what Joe said.

 

I got a 242 going into my MJ behind an AX5....soon. Good to hear yours is behaving well behind your AX15 Joe, there's not too many running one behind a manual.

 

Jeff

[Eliminator89]

Ok, bringing this back with a few questions.

 

I have located a '93 front axle locally. The fellow tells me the CV boots are ripped. CVs on a '93 axle? I thought only the earlier axles used CVs. Am I wrong on that? Is he wrong on the year of his axle? Or did the axles use boots with the u-joints and he is just confused about it having CVs when it really doesn't?

[mjeff87]

could be a ZJ axle...they used CV's.

[Eliminator89]

How do I recognize a ZJ axle?

[Eagle]

I don't know the systems on the MJ/XJs very well. I hear of vacuum disconnect front axles and non-disconnect axles. As I understand things, the vac axles are high-pinion and the nons are low-pinion. The vac axles are in earlier trucks and the nons are in later trucks. The non have larger u-joints on the axles and the vacs have smaller joints.

 

So, the nons are a bit stronger but you lose the high-pinion advantage. That shouldn't be a problem as I will not be lifting the MJ.

Your information is a mixed bag of mostly incorrect opinions.

 

*FACT: Some early axles had vacuum disconnects. That would be the axles used with the Command-Trac transfer cases. The option Selec-Trac transfer cases had a full-time 4WD option and never used axles with disconnects. So you can get early non-disconnect axles.

 

*FACT: ALL MJ axles and all XJ axles through 1999 were high pinion -- regardless of whether or not they had a disconnect, and regardless of u-joint size.

 

*FACT: When the larger u-joints were first used (around 1991 or 1992?) they were used only in the vehicles with ABS, while vehicles with standard brakes got the smaller u-joints. It was not based strictly on year.

 

I also would like full-time but hear the 242 is not that strong. I have a 219 in the shed. I also have a 208 (I know, not full-time) in the shed also. Both are from behind 727s (Jeeps) and I have an AX15 in the MJ.

 

So, it seems it would be easier for me to get a 4 wheeldrive AX15 (external slave this time, no more $700 slave replacements) and a 231 and forget the full-time. But I would REALLY like to have full-time. The truck will see mostly street use with an occasional trail ride (no level 3 or 4 trails).

The 242 is slightly less strong than the 231, but it's plenty strong for the wheeling you are describing. I've wheeled with guys in NAXJA who are much more "built" than what you seem to intend, and run much tougher trails than you seem to expect, and they couldn't break a 242. Plus -- you can beef it up with parts from a Dodge truck, or even get the guts from a Hummer 242. (But you don't need them.)

 

Did the 242 come behind the AX15?

No.

 

If not, can I put one there anyway?

Yes.

 

You guys don't mind giving opinions do you?

No ...

[Eagle]

How do I recognize a ZJ axle?

It'll be low pinion, and may have CV joints rather than u-joints. '93 was the first year for the ZJ -- they used CV joints that year.

[Eagle]

"some non-CAD axles had CV joints as well"

 

CV joints at the knuckles or the driveshaft? CAD mean Center Axle Disconnect?

 

Both

[Eliminator89]

Thanks guys. All this helps.

 

I emailed the guy for clarification of what he has.

 

Eagle, I'm not an off-roader. I wouldn't mind driving the woods to a camp site but rocks and rugged trails are not my cup of tea. So those bigger u-joints will not be the deciding factor if I by a certain axle or not. If I find an axle with them, I'll get it but I'm not going to search the country for them.

 

Looks like I just need to avoid the CV joint axles and the disconnect axles and I'll be just fine. An ABS axle should be good also, I'll just have a few parts on it that I won't be using.

[rockhardzj]

Thanks guys. All this helps.

 

I emailed the guy for clarification of what he has.

 

Eagle, I'm not an off-roader. I wouldn't mind driving the woods to a camp site but rocks and rugged trails are not my cup of tea. So those bigger u-joints will not be the deciding factor if I by a certain axle or not. If I find an axle with them, I'll get it but I'm not going to search the country for them.

 

Looks like I just need to avoid the CV joint axles and the disconnect axles and I'll be just fine. An ABS axle should be good also, I'll just have a few parts on it that I won't be using.

CV axles are perfectly fine if your just taking a light trail to a campsite. once you get into more difficult offroading, they become less of a desired item. But they are great for daily driving, winter driving and such.

 

Disconnect axles, I'd personally avoid at all costs adds more things that can go wrong.

[Eliminator89]

Right Joel. No lift, no big tires, no hot engine, no real off-roading. Just want to make the truck 4 wheeldrive.

 

We get good snowfalls around here in winter and I need to get to work, Work is 20 miles away along state roads, county blacktops and an interstate. Fulltime 4 wheel drive is advantageous. Friends and family are up to 100 miles away.

 

I'm not going to worry about locating an axle with the big u-joints but its nice to know what I am looking at and what I might want to avoid.

[Eagle]

If you can find a non-disconnect axle at a price that's "right" to you, by all means buy it. But I wouldn't say you have to avoid the disconnect axles at all costs. The kind of use you have in mind won't break one. And it's easy to simply engage it manually, shim it in the engaged position, and replace the shift motor to make it functionally the same as a non-disconnect. Presto, no more worries about vacuum leaks.

[rockhardzj]

If you can find a non-disconnect axle at a price that's "right" to you, by all means buy it. But I wouldn't say you have to avoid the disconnect axles at all costs. The kind of use you have in mind won't break one. And it's easy to simply engage it manually, shim it in the engaged position, and replace the shift motor to make it functionally the same as a non-disconnect. Presto, no more worries about vacuum leaks.

You can also rig it up to be a cable actuated unit, very reliable.

[carnuck]

If you are going full time without serious wheeling or lift, I would go a CV axle from a ZJ with V8. I have an AW4/242 going into my '87 MJ (as soon as I finish moving and a few other projects) and I test fit a NP208J with AX-15 (You need the thick spacer from Partsmike to make it work) I am currently doing an AW4/NP208J in my '83 J10. If the weather clears up today, I'll get some more done (need another FSJ trans crossbar to butcher to fit)