Full time 4wd

How exactly do you engage the fulltime 4wd. I put my jeep in N and engage the 4wd to high in order to get the part time 4wd. But what about fulltime, or does all models have fulltime? 99 xj sport 4.0

Your shift bezel should have a full time option, if you have a select trac transfer case, or np242.

I'm thinking you probably have the np231.

99 doesn't have the full time option. Only part-time (np231). I think they did away with the np232 (full-time) after 98. Someone correct me if i'm wrong.

What does your T-case bezel have printed on it?

If it has '2-hi, 4-hi, N, 4-lo' then it's the part-time NP 231.

If it has '2-hi, 4-part time, 4-full time, N, 4-lo' then it's the part-time/full-time NP242.

Both models are 'shift-on-the-fly' types, which means you can shift them to 4wd up to 60 kph. (I think that's 35 mph...) Shifting into 4-low must be done standing still, or moving less than 2 mph. (I just put it in neutral sitting still and then shift.)

Does that help?

Thanks. I don't have full time 4wd that sucks.

tupton said:

99 doesn't have the full time option. Only part-time (np231). I think they did away with the np232 (full-time) after 98. Someone correct me if i'm wrong.

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You're wrong

The NP242 was available as an option right up to the end in 2001 - my 2000 has one. It was never dependent on model year in the '87-up era, but rather trim level and/or ordered options.

Sport cherokee said:

Thanks. I don't have full time 4wd that sucks.

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Not really. With shift on the fly you can handle about anything weather-wise. If the pavement conditions improve enough that your tires start to grab, disengage it. If you see a patch of snow pull the lever. You don't have to stop or shift out of drive.

On snow-covered roads, and we just had 14" in the last 2 days, I leave the 4WD engaged and just drive.

Sport cherokee said:

Thanks. I don't have full time 4wd that sucks.

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You do know you still have shift on the fly right?
No need to stop and put it in N to shift to "part time". You can just drive and shift back and forth between 4 hi and 2WD.
Now if you want to go to 4Lo, you need to stop and put the tranny in N.

My 99 has full time, but my 96 only has part time. Honestly, I haven't come across a situation yet this year that I wished I had full time on the 96 (the 96 is my DD). Even with all the snow we've gotten in PA in the last couple weeks and periods of icy roads/patchy roads I've never had a problem.

When I bought my 99 I was dead set on getting the 242, but after running the 96 with only the part time option, I'd never let the full time option govern a decision of to buy or not to buy a vehicle.

Even in 2wd, if you have some weight in the back you should be pretty well off.

XJPhoenix said:

Both models are 'shift-on-the-fly' types, which means you can shift them to 4wd up to 60 kph. (I think that's 35 mph...) Shifting into 4-low must be done standing still, or moving less than 2 mph. (I just put it in neutral sitting still and then shift.)

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Actually, 4Hi and 4Full-Time can be engaged at speeds up to 55mph, but when in 4hi, you should not exceed 4hi (and if you're going that fast and need four wheel drive, you probably shouldn't be going that fast to begin with).

As for 4lo, it's best to engage rolling in neutral at 2mph. As far as rolling forwards or backwards, I dont think it really matters, but i've always done forwards. Sometimes you can get it in 4lo sitting still, it's just better for everything to do it rolling

As far as the full time option, I wouldn't give it up. I've got the 242 on my XJ and the 231 on my mom's KJ. About 3 years ago (our last snow storm) I remember we were out driving the KJ and the main roads were clear, but the side streets were still snow packed, and it got to be a pain having to shift in and out every time we turned onto or off of a main road. Where as, had I had my XJ at that time, I could just set it in 4full time and forget about it.

Next Jeep I get will definitely have the 242.

99XJSPORT06 said:

Actually, 4Hi and 4Full-Time can be engaged at speeds up to 55mph

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Okay, this brings up something I've been wondering about for some time: the 55mph limit on engaging 4HI. While I don't have the owners' manual to hand, I seem to remember that the wording was something to the effect of '4HI can be engaged at any highway-legal speed' - no actual speed limit was mentioned. What I'm wondering about was if the wording was changed after the federal 55mph limit was repealed, but 55 still gets repeated as the magic number.

but when in 4hi, you should not exceed 4hi (and if you're going that fast and need four wheel drive, you probably shouldn't be going that fast to begin with).

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Agreed. I use 4FT here in the rain because we don't surface the roads for bad weather and have driven with it engaged in shorts bursts up to about 75mph - but unless there's absolutely nobody around on a completely empty road, that's still too fast for the circumstances in this vehicle.

Next Jeep I get will definitely have the 242.

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If only they'd do a 241J with full-time mode, I'd be happy...

I think the 55MPH limit is just an arbitrary limit. Theres no mechanical reason why you cant engage 4Hi at any speed.

99XJSPORT06 said:

Actually, 4Hi and 4Full-Time can be engaged at speeds up to 55mph, but when in 4hi, you should not exceed 4hi (and if you're going that fast and need four wheel drive, you probably shouldn't be going that fast to begin with).

As for 4lo, it's best to engage rolling in neutral at 2mph. As far as rolling forwards or backwards, I dont think it really matters, but i've always done forwards. Sometimes you can get it in 4lo sitting still, it's just better for everything to do it rolling

As far as the full time option, I wouldn't give it up. I've got the 242 on my XJ and the 231 on my mom's KJ. About 3 years ago (our last snow storm) I remember we were out driving the KJ and the main roads were clear, but the side streets were still snow packed, and it got to be a pain having to shift in and out every time we turned onto or off of a main road. Where as, had I had my XJ at that time, I could just set it in 4full time and forget about it.

Next Jeep I get will definitely have the 242.

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Good to know!

When I bought this XJ, I really really wanted the 242. I had the 231 in my old 1991, and it worked great, but I was paranoid about hitting a dry patch of road and not taking it out of 4wd. (The roads I used to travel were very rural, and the trees would shelter it in places leaving short stretches of dry road.) However, when I found my current XJ, it was in such good shape and the t-case worked soooooo smooth; I just had to buy it. And truth be told, I haven't actually needed 4wd so far! I've had it in 4wd just for giggles, and to show off for my dad. (Now he wants an XJ!)

I never knew that it was easier on the Jeep to be rolling and shift it.

Sport Cherokee: It's not too bad. The 231 is a great little t-case; cheaper to buy and easier to work on. There are literally tons of upgrades that can be done to this unit, whereas the 242 is limited to a handful of aftermarket goodies. For instance...

The 231 has dozens of different 'slip yoke eliminator' kits available, while the 242 is limited to a 'hack & tap.'

The 231 can be built to have '2-low' engagement, while the 242 cannot. (Currently.)

The 231 has a heavy-duty kit, while the 242 doesn't. (Mind you, it's plenty strong already.)

The 231 can get lower gear sets to improve the 4-low range, the 242 doesn't have any options to get lower gearing.

And finally, you can always swap a 242 into your Jeep; it's cheap if you buy one used, and it bolts right in. All you need is the t-case, the linkage (not sure which part is needed, so grab it all)the driveshafts and the shifter bezel.

casm said:

You're wrong

The NP242 was available as an option right up to the end in 2001 - my 2000 has one. It was never dependent on model year in the '87-up era, but rather trim level and/or ordered options.

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I stand corrected!

casm said:

Okay, this brings up something I've been wondering about for some time: the 55mph limit on engaging 4HI. While I don't have the owners' manual to hand, I seem to remember that the wording was something to the effect of '4HI can be engaged at any highway-legal speed' - no actual speed limit was mentioned. What I'm wondering about was if the wording was changed after the federal 55mph limit was repealed, but 55 still gets repeated as the magic number.

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You're not the only one who wonders about this. Here's what I show others who bring up this point.

Clicky ---> http://www.jeep.com/4x4/

Once there, click on where it says "Get to know the Jeep 4x4 Systems" under the "Get Ready" tab. Once this anamation loads, it brings up all the current model Jeeps and the transfer cases offered. For this situation, I go by the Liberty transfer cases, as they are the same 231 and 242 cases that were used in the XJ's. So now, click on either of the two Liberty pictures, "Hands On" being the Command-Trac (231), or "Multi-Option" being the Selec-Trac (242). Clicking on either of these will load a short video tutorial of how the two transfer cases work, and the appropriate methods/limits of each selection.

casm said:

Agreed. I use 4FT here in the rain because we don't surface the roads for bad weather and have driven with it engaged in shorts bursts up to about 75mph - but unless there's absolutely nobody around on a completely empty road, that's still too fast for the circumstances in this vehicle.

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Oh yes. 4FT has come in VERY handy in the rain now. Even though 90% of my driving is highway now, and I stay in 2wd while on the highway, the other 10% is on two lane country back roads with sharp curves, and surfaces that haven't been re-paved in god knows how long. Seeing as how my tires are quicly wearing out, 4FT really helps to keep me from being all over the place, even if I stay with in safe speeds.

Ray H said:

I think the 55MPH limit is just an arbitrary limit. Theres no mechanical reason why you cant engage 4Hi at any speed.

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Ok, get on the highway and throw it in 4Hi while you're running about 70-75mph and tell me what happens.:explosion

I dont generally drive over 70 so I probably wont take you up on that. I know I have engaged mine above 55 before and had no bad effects from doing so. That blows the theory that it will self destruct above 55 out of the water right there.
Can you tell me exactly what inside of the transfer case will be destroyed and why from engaging it above 55?
If you dont know, just say you dont know. If you do know, please tell me because Im sure I dont know.

i engaged my 242 at 70mph into full-time mode weekend before last. nothing special happened. (except it went into 4FT)

Its not so much that it could blow up the minute you shift it in, it's more along the lines of driveline binding. And that pressure that builds up in the driveline (especially if you are running it on dry pavement) has to be released somewhere.

Besides, if you're going over 55 and need 4x4, chances are, you shouldn't be going over 55.

If Im not mistaken, you need to pass through part time to get to fulltime in the 242, right. So technically, you engage part time to get to full time. Does the 242 come with a warning not to engage it above 55 because I could see where you would have reason to use fulltime above 55? Im asking because Ive got a 231 and not a 242.

Ray H said:

If Im not mistaken, you need to pass through part time to get to fulltime in the 242, right. So technically, you engage part time to get to full time. Does the 242 come with a warning not to engage it above 55 because I could see where you would have reason to use fulltime above 55?

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Yes you do pass through part-time, however, it's for such a short period of time (under a second if you shift normally), that the t-case doesn't have a chance to get into 4hi, and goes straight into 4FT. And yes, I can see how one could need 4FT at speeds greater than 55. But again the way I look at it is, if you need 4x4 at all ( no matter what setting) you probably shouldn't be going that fast given the road conditions, or atleast say no faster than 60, possible 65 (if you're refering to a rainy condition when using 4FT)