4hi question

hardhittinz · **Joined:** Tue Jul 03, 2007 10:44 pm **Posts:** 195

i got part time 4 wheel drive and it is suppose to snow here this weekend and my tires (st's) are crappy and the wife has some christmas shoppin to do so would it be ok or hurt anything by throwin it in 4 hi and rollin out to shop????? also if i get up and there is snow whats the best way to engage 4 hi? do it while engine off?will runniin and in N or do you go to be rollin? srry been awhile

QuestMan · **Posted:** Thu Dec 17, 2009 11:04 pm

Part-time is ONLY for slippery surfaces (Dirt roads, SNOW or ICE covered), etc. If you get onto dry pavement, AND turn, you'll experience 'driveline bind'. At the least, when you turn, the back will 'hop', since the front axle and rear axle are locked together. On a slippery surface, the tires will slip, so it's not an issue. So, if you're on a slick surface, (completely snow-covered, for instance) drive away! If you're on dry pavement, DON'T turn......(Or bad, bad, things will happen) :shock:

Snow, then pavement, then snow, is trickier, so I can't answer that one. If you, by any chance have selec-trac, then put it in full-time and drive ANYWHERE, since it's designed to work on any surface.

I think that's the gist of it. I'm sure there are others who can do a better job of describing the problems of drivng in 4wheel, while on dry pavement. Since I have selec-trac, I just put in full-time, and pretty much leave it that way until spring. Oh, and if you have a limited-slip, add some weight to the rear-end, or your jeep will tend to slide around when it's slick. I learned THAT lesson while driving in my postal. :oops:

P.S. to engage 4 wheel drive, just pull that lever up while moving, and DON'T hesitate when you pull the lever.

tjkj2002 · **Posted:** Thu Dec 17, 2009 11:54 pm

Also do not drive straight on a dry surface in part time 4wd.The front and rear diffs are slightly geared differently so the front axle will always turn just a tad faster then the rear axle will,and no you can not change that.

LibertyFever · **Posted:** Sat Dec 19, 2009 11:06 am

I remember my test drive in my first 4WD, a Jeep Liberty. I wondered why the tires would "scrub" when I tried a sharp corner. Since buying my first Jeep I've had this conversation with a lot of people.

Basically Part-Time 4WD is supposed to be used part-time, go figure Eh?

I believe the 02 to 07 Liberty's had either a NV231 Command-Trac Part-time transfer case (found on the Sport) or the NV242 Selec-Trac Full-time transfer cases (found on the Limited). I don't know which transfer case came on the Renegades.

Both these transfer cases are considered "shift on the fly" which means you can slide in into and out of 4WD Hi while driving. 4WD Lo is another story. I still haven't figured out a foolproof way to do it without some grinding even when the transmission is in neutral.

So to get back to your question, if you have the NV231 Command-Trac Part-time transfer case (found on the Sport) then you should drive in 2WD until you think the road surface has become slippery then slip it into 4WD Hi. But as said before don't drive about on pavement in 4WD or else you may damage the transfer case.

Of course if you're lucky enough to have a NV242 Selec-Trac Full-time transfer cases (found on the Limited) then go ahead. You can drive all winter in 4WD. It has a special clutch pack. However don't drive trails in 4WD Full-time because I have heard of people burning out their transfer case clutch packs. Use 4WD Part-time selection.

I hope this clears up any questions you had.

CRD Joe · **Posted:** Sat Dec 19, 2009 12:54 pm

Its nice to have an NV242 so you have a FULL time four wheel drive system as well. Kind of an ALL wheel drive system.

Good advice given here.

hardhittinz · **Joined:** Tue Jul 03, 2007 10:44 pm **Posts:** 195

well i only got part time sucks lol but it is what it is.Well the roads here today are complete blankets so i went to pull out my drive way started spining and pulled lever into 4hi and away i went i drove like 3 miles down the road in 4hi with my parttime and turned and all with no issues or noises.. when i parked back home i left it in 4hi now to get back into 2hi what do i do?same drive and force lever back down? do it while parked or whats the best way?

tjkj2002 · **Posted:** Sat Dec 19, 2009 2:22 pm

LibertyFever wrote:

I remember my test drive in my first 4WD, a Jeep Liberty. I wondered why the tires would "scrub" when I tried a sharp corner. Since buying my first Jeep I've had this conversation with a lot of people.

Basically Part-Time 4WD is supposed to be used part-time, go figure Eh?

I believe the 02 to 07 Liberty's had either a NV231 Command-Trac Part-time transfer case (found on the Sport) or the NV242 Selec-Trac Full-time transfer cases (found on the Limited). I don't know which transfer case came on the Renegades.

Both these transfer cases are considered "shift on the fly" which means you can slide in into and out of 4WD Hi while driving. 4WD Lo is another story. I still haven't figured out a foolproof way to do it without some grinding even when the transmission is in neutral.

So to get back to your question, if you have the NV231 Command-Trac Part-time transfer case (found on the Sport) then you should drive in 2WD until you think the road surface has become slippery then slip it into 4WD Hi. But as said before don't drive about on pavement in 4WD or else you may damage the transfer case.

Of course if you're lucky enough to have a NV242 Selec-Trac Full-time transfer cases (found on the Limited) then go ahead. You can drive all winter in 4WD. It has a special clutch pack. However don't drive trails in 4WD Full-time because I have heard of people burning out their transfer case clutch packs. Use 4WD Part-time selection.

I hope this clears up any questions you had.

The 231 command trac was standard on all KJ's besides the CRD's(select trac only),the 242 select trac was a option for all KJ's but the CRD(which it was standard).

To the OP...........
With the command trac you can shift back into 2wd at a stand still,it's the select trac that has the shifting issues.

hardhittinz · **Joined:** Tue Jul 03, 2007 10:44 pm **Posts:** 195

ok and the command trac is what i got on my sport with part time :?:

LibertyFever · **Posted:** Sat Dec 19, 2009 11:29 pm

CRD Joe wrote:

Its nice to have an NV242 so you have a FULL time four wheel drive system as well. Kind of an ALL wheel drive system.

Good advice given here.

I'm actually considering the idea of an upgrade to the NV242 transfer case.
Wait a minute, I wonder if I could actually fit a Rubicon transfer case (NV241OR) into a Libby? hmmm....

Did you realize that the NV241 transfer case is actually very similar to the NP 231 found in most Wranglers? I was genuinely surprised, I mean they don't bother to call it Part-time when it's in a Wrangler.

tjkj2002 · **Posted:** Sat Dec 19, 2009 11:36 pm

LibertyFever wrote:

CRD Joe wrote:

Its nice to have an NV242 so you have a FULL time four wheel drive system as well. Kind of an ALL wheel drive system.

Good advice given here.

I'm actually considering the idea of an upgrade to the NV242 transfer case.
Wait a minute, I wonder if I could actually fit a Rubicon transfer case (NV241OR) into a Libby? hmmm....

Did you realize that the NV241 transfer case is actually very similar to the NP 231 found in most Wranglers? I was genuinely surprised, I mean they don't bother to call it Part-time when it's in a Wrangler.

The Rubicons RockTrac t-case is a part time case,only can use 4hi on loose/slippery surfaces just like the 231.Just the RockTrac is a purpose built t-case that is 1 ton rated with 4:1 low range make just for the Rubicons and offered in no other vehicle.

hardhittinz · **Joined:** Tue Jul 03, 2007 10:44 pm **Posts:** 195

ok guys now i got a problem 4hi worked great no problems at all until today i put it in 4 hi and the parttime light didnt show on dash though it was in 4hi so i put it back in 2hi and the light comes on so now in 2hi i got the parttime light whats the deal with that?

Dje Ryu · **Posted:** Sun Dec 20, 2009 6:49 pm

your t-case shifter position sensor is going out. It's not that critical. You can either replace it or just keep driving... it may even just go away and start working properly, again.

hardhittinz · **Joined:** Tue Jul 03, 2007 10:44 pm **Posts:** 195

ok cool thanks for the info.I dont mind long as the 4wd still works though im sure that parttime light will annoy the old lady with in a few days lol

QuestMan · **Posted:** Wed Dec 23, 2009 12:53 am

A little off-topic but........do or DID any of the wranglers EVER offer selec-trac? I love the selec-trac tcase in my libby, and it was one of the reasons I chose her over a wrangler.

FreedomKJ · **Posted:** Wed Dec 23, 2009 4:01 pm

LibertyFever wrote:

Of course if you're lucky enough to have a NV242 Selec-Trac Full-time transfer cases (found on the Limited) then go ahead. You can drive all winter in 4WD. It has a special clutch pack. However don't drive trails in 4WD Full-time because I have heard of people burning out their transfer case clutch packs. Use 4WD Part-time selection.

The "clutch" in the 242 isn't a clutch like you have in a manual transmission, It's just a splined, hollow shaft that slides in and out of the center differential to either lock it or unlock it. The center differential on the 242 is just a plaetary gearset with the same input and output speeds.

There should be no issue driving in full time off road, aside from the reduced traction vs. part time.

sleeve84028 · **Posted:** Thu Dec 24, 2009 8:53 am

Anyone have an exploded view of the 242 internals?

ATXKJ · **Posted:** Thu Dec 24, 2009 11:53 am

sleeve84028 wrote:

Anyone have an exploded view of the 242 internals?

Try this
http://www.jeep4x4center.com/jeep-transfer-case/np-242-parts.htm

the Diff cluster #25 has 2 nested gears with planetaries - that's Full Time 4x4
on a 231 or 241 - that cluster is 1 solid gear - that's why they have higher torque ratings

and the springs on the shifter forks - those are what the shift lever pushes against
and if the gears are turning exactly the same they will shift
if there's a difference front to rear - tires sizes/pressures ect.
- the gear won't engage (or dis engage)

LibertyFever · **Posted:** Thu Dec 24, 2009 8:33 pm

WoW, you guys are a wealth of knowledge.

4hi question

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