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im stupid

husky250rider

NAXJA Forum User
Location
St Louis MO
ok u guys might think i am retarted but i just got my xj yesterday and i dont know how to turn on full time 4wd every time i put it in 4h or 4l it says part time can someone help me
 
husky250rider said:
ok u guys might think i am retarted but i just got my xj yesterday and i dont know how to turn on full time 4wd every time i put it in 4h or 4l it says part time can someone help me
We need to know what 4WD system you have?
 
Well, that depends...

How many "shift" positions do you see on the tcase shifter bezel?

If it's 2HI - 4HI - N - 4LO, you don't have "full-time" 4WD, and you'd best not leave it in 4WD while in the dry or on pavement

If it's 2HI - 4PT - 4FT - N - 4LO, then you do have the "full-time" setting, and you can theoretically leave it in "full-time" 4WD indefinitely (but you really shouldn't - if nothing else, you'll see the hit in fuel mileage.)

There were at least two transfer cases in production at any given time - with the main two after 1987 being the NP231 (w/o 4FT) and the NP242 (w/4FT.) The NP231 is far more common - I've only seen the FT option (NP242) in "Limited" Cherokees - but I could be wrong.

If you can't tell from up top (say, the bezel is missing or has been incorrectly replaced,) it's still possible to tell. Get under the truck, and look at the transfer case/back side/opposite the front output shaft. There should be a small (about 2") round metal tag with a screw thru the centre. You might have to clean it (it's silver with a red "tooth" edging,) but it's an ID tag for the transfer case and it should read, up top, either 231 or 242 (may or may not have a "J" after it, for "Jeep" production.)

Let us know what you find.

5-90

(You're not stupid, just inexperienced and untrained. Give us time, we'll warp your mind...)
 
5-90 said:
Well, that depends...

How many "shift" positions do you see on the tcase shifter bezel?

If it's 2HI - 4HI - N - 4LO, you don't have "full-time" 4WD, and you'd best not leave it in 4WD while in the dry or on pavement

If it's 2HI - 4PT - 4FT - N - 4LO, then you do have the "full-time" setting, and you can theoretically leave it in "full-time" 4WD indefinitely (but you really shouldn't - if nothing else, you'll see the hit in fuel mileage.)

There were at least two transfer cases in production at any given time - with the main two after 1987 being the NP231 (w/o 4FT) and the NP242 (w/4FT.) The NP231 is far more common - I've only seen the FT option (NP242) in "Limited" Cherokees - but I could be wrong.

If you can't tell from up top (say, the bezel is missing or has been incorrectly replaced,) it's still possible to tell. Get under the truck, and look at the transfer case/back side/opposite the front output shaft. There should be a small (about 2") round metal tag with a screw thru the centre. You might have to clean it (it's silver with a red "tooth" edging,) but it's an ID tag for the transfer case and it should read, up top, either 231 or 242 (may or may not have a "J" after it, for "Jeep" production.)

Let us know what you find.

5-90

(You're not stupid, just inexperienced and untrained. Give us time, we'll warp your mind...)


it has 2h n 4h 4l now i understand. thanks alot for the info
 
Re-read my earlier post. If the bezel hasn't changed, you can tell from the driver's seat. Still, it should be confirmed, so take a minute to crawl under anyhow (and get used to that position, you'll be there a lot in the next several years...)

If you climb down under the driver's door, you should get right to the tag.

5-90
 
husky250rider said:
it has 2h n 4h 4l now i understand. thanks alot for the info

Then you don't have "Full Time" four-wheel drive, and most likely an NP231 transfer case (although I'd still want to eyeball the tag, if it was my rig.)

The NP231 is still a good case, and should give you years of service. Make sure to use Dexron II/III when you change the fluid, and not gear oil. If you have an automatic, it's the same fluid you'll want to use in there (although they don't mix in normal operation.)

5-90
 
Yes everyone is right, you don't have full time 4wd. I think you are confused like I was when I got my cherokee. Because Jeep names thier 4wd operations backwards from the way my mind works. Maybe I'm just weird but I would think that part time would mean somthing kind of like all wheel drive, if you had it on part time it would be 2wd until you needed 4wd thus only being in 4wd part of the time. And when you put it in full time it would be in 4wd all the time or full time. But it is opposite of that. The part time and full time refer to when you should use it not how it operates. Just my thoughts. If no one was seriously confused by all that then I will be surprised.
 
5-90 said:
- I've only seen the FT option (NP242) in "Limited" Cherokees - but I could be wrong.


It was available as an option in any package. I have one in a base model, that originally was a government fleet cherokee. Also I had one in an 88(I believe) Chief, that the original owner ordered almost every stinking option.

I think they may have come in the Wagoneer also though. I remember one in a Waggy I was looking at.
 
If you have the 5 speed, it wouldn't have even been available on that truck since they only got the 231 case. IIRC the 242 wasn't available on any of the civilian base model offerings, only the "cop" one had that, and it was standard (and I think manditory on the 4wd too, no 231's). We used to have an '88 model year base model stripper truck that had the 242, and from I could tell it wasn't a "cop" truck, just an oddly optioned base model.
 
sjx40250 said:
Part time locks the TC between the front and rear drive shafts - 50/50 split. FT is open (40/60?).

can anyone comfirm those ratios?

basically, the 242 acts like a differential, allowing the front and rear wheels to spin at different speeds without binding. (while cornering on dry pavement)

I have a 231, and try not to use it unless I can't get any traction with just the rear wheels. - even in heavy rain I get some unhealthy sounding noises, so I limit it to deep snow or loose gravel/mud.

oh, and another way to check, at least on the newer XJs, is to look behind the driverside sunvisor: for the 231 you should have a sticker that says "Command-Trac", and warns against use of 4wd in high traction situations, for the 242, it should say "selec-trac"



B
 
sjx40250 said:
Part time locks the TC between the front and rear drive shafts - 50/50 split. FT is open (40/60?).

OK I get the first one, they are locked together.

The second one I have trouble swallowing. With Full time, there is a differential, sort of like in an axle. The way I understand it, if both axles have a good grip, the distribution should be 50/50. If say the rear axle looses traction, more power will be sent to the back and less in the front, and visa versa. If the front looses traction, more power goes to the front, and less to the back.
 
Zuki-Ron said:
OK I get the first one, they are locked together.

The second one I have trouble swallowing. With Full time, there is a differential, sort of like in an axle. The way I understand it, if both axles have a good grip, the distribution should be 50/50. If say the rear axle looses traction, more power will be sent to the back and less in the front, and visa versa. If the front looses traction, more power goes to the front, and less to the back.

That's how I understand it, but if you're in that much trouble, you'd probably need to stick it in part-time. I think it's supposed to be 48/52, but don't quote me on that, I read it in JP!
 
I asked the same question about the part-time thing. it was amusing.
either way - the hubs lock and they lock in real hard while in 4hi - of course thats only after you roll around a bit.

the 4lo hub locking occurs a little quicker, you can feel it once it does
 
yup, I got the 242 in a 99 Sport...Didn't know about the whole 5speed only got the 231 thing...interesting.

You might also, in your future readings on this sight, see them referred to as "command-trac" (NP231, 2HI, 4HI, N, 4LO) and "selec-trac" (NP242, 2HI, 4HI, 4FT, N, 4LO). You in this case, have command-trac. As to which is better, it's a toss up. I believe the 231 has been around longer than the 242, but both are pretty darn reliable from my readings on here, with proper care. I'm partial to the 242. I find the Full Time option very handy now in the winter time when you come up on a road that has had the snow plowed off and it dry, and you turn on to a side street and are right back into the snow again. I can throw it in Full Time and forget about it. Whereas in your case, you'd have to shift out of 4HI back into 2HI on the dry road, and then back to 4HI again once you got to a road not cleared.

I also find the Full Time option to be handy in those "OMFG" rain storms where it's impossible to maintain good traction, no matter what tires your running.
 
XplodJeepster said:
I asked the same question about the part-time thing. it was amusing.
either way - the hubs lock and they lock in real hard while in 4hi - of course thats only after you roll around a bit.

the 4lo hub locking occurs a little quicker, you can feel it once it does

What are you talking about?

it's my understanding that the hubs are always locked, hence the "Live" front axle.

older jeep 4x4s with automatic locking hubs had to be rolled forward or backward up to 20 feet to engage/disengage the hubs, but not with the shift on the fly style 4wd our cherokees have
 
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